Bosch gas cooktop installed (C) Daniel Friedman How to Install a Gas Cooktop

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Gas cooktop installation steps:

This article provides a step by step instructions show how to prepare the countertop opening, how to make gas & electrical connections, how to position and how to test the glass cooktop. The article also illustrates how to clear obstructions that get in the way of fitting the cooktop into the countertop.

We also discuss gas piping & how to test for gas leaks in the cooktop piping & where to locate gas shutoff valves.

This article series explains the steps in installing & testing gas appliances and includes a detailed procedure for converting from LP gas or "bottled gas" to natural gas or "piped in gas" at a building.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Gas Stovetop or Cooktop Installation Details

Preparing the gas cooktop gas inlet pipe nipple for installation of a flare adapter (C) Daniel FriedmanArticle Series Contents

Gas Cooktop Installation Starting Point: Turn off the Gas Supply

Bosch gas cooktop ready for installation into a countertop (C) Daniel FriedmanWatch out: before even starting a gas-cooktop installation, confirm that the new gas appliance has been properly set-up for the type of gas fuel to be used.

The photo at left shows the red sticker indicating that this gas cooktop has been converted for use with propane - LP gas. Never connect an appliance set up for natural gas to an LP gas supply or vice versa. The appliance will not work properly and it will be unsafe.

Watch out: Most manufacturers require that installation and fuel conversions shall be performed by a trained and qualified service technician and local building regulations may require gas appliance installation by a licensed professional.

The appliance installation technician should be sure to correctly identify the model number of your gas appliance so that s/he can follow the correct details of the manufacturer's instructions.

Here we show the outdoor gas shut-off valve for the gas cooktop in its OFF position - the red handle is at right angles to the gas piping direction.

Watch out: it would be smart to locate not only the local shut-off valves at the gas appliance but also the main gas shut-off valve for the building. Should there be a leak or other problem at the local gas supply shut-off valve(s) you will be glad that you also shut down the gas supply at the building main.

Remove the Old Gas Cooktop

Watch out: be sure that the gas supply has been turned off before beginning this step.

Jennair glass gas cooktop to be replaced in this procedure (C) Daniel Friedman Jennair glass gas cooktop to be replaced in this procedure (C) Daniel Friedman

At above left is the fifteen-year-old Jennair glass cooktop that is being replaced in this procedure. You'll need a pair of wrenches that fit the flexible gas line and the brass adapter that has been screwed to the cooktop's gas pipe nipple: turn these wrenches in opposite directions to loosen the gas line and remove it from the cooktop.

Measure Before Ordering & Again Before Installing a Gas Cooktop

You will need a measuring tape and should have already used it to make triple sure that the new gas cook top will fit into the countertop opening.

Measure the countertop opening length and width and the depth between the countertop surface and any obstructions below such as a built-in oven or other piping or cabinet components.

For complete details on making countertop measurements before buying & installing a cooktop,

Watch out: After you have removed the old gas cooktop (if one is installed) test-fit the new one in the opening before proceeding to hook up gas piping or electrical wiring.

Clean and prepare the countertop surface & the appliance enclosure

Jennair glass gas cooktop to be replaced in this procedure (C) Daniel Friedman Jennair glass gas cooktop to be replaced in this procedure (C) Daniel Friedman

At above left we are removing old grease and silicone sealant that had marked the edges of the old cook-top that was removed.

At above right you can see the flexible gas piping and the black top of the built-in oven installed below this cook top. The presence of the built-in oven means that we will have to work carefully in locating and routing the gas connections and regulator and wiring as space is limited.

Test that the new cooktop fits into the countertop

If you don't do this, including checking for gas piping and electrical wiring clearances before hooking things up you'll be sorry.

Bosch gas cook top being test-fit into the countertop opening (C) Daniel Friedman Bosch gas cook top installation measurements (C) Daniel Friedman

I told you so! The countertop opening through the granite countertop was properly sized to accept the Bosch gas cooktop, but still the unit did not fit down into the opening! The photo at above left shows our new cook top resting on something - a ledge of plywood that extends into the opening below the countertop.

What the heck? The cut-out in the granite counter top was big enough but as you can see in the two photos below, a ledge of plywood from a cabinet side and a piece of plastic cabinet bracket extend into the space wanted by the body of the new gas cooktop.

Bosch gas cook top installation measurements (C) Daniel Friedman Bosch gas cook top installation measurements (C) Daniel Friedman

Remove Obstructions to Make the Cooktop Fit Properly

Adjust or remove any gas cooktop clearance obstructions in the countertop opening if needed. Here is where the professionals earn their big bucks.

Mark the segment of cabinet wall to be removed (C) Daniel Friedman Removing a slice of plywood to make the cooktop fit with adequate clearance (C) Daniel Friedman

My mom would maybe have sent the whole cooktop back and waited two years for the production of a custom unit to fit this funny opening. There is just no nice neat way to run a power saw in this opening to cut away the intruding material.

At above left we mark the depth of material to be removed and draw a straight cut line. At above right the hammer and chisel get to work. The drop cloth is both to help protect the top of the built-in oven below and chiefly to avoid dropping a lot of wood chips down into an opening where I'd rather not leave fire-kindling.

Removing a slice of plywood to make the cooktop fit with adequate clearance (C) Daniel Friedman Removing a slice of plywood to make the cooktop fit with adequate clearance (C) Daniel Friedman

But as a retired carpenter I have a chisel and a hammer. Having made a chiseled horizontal cut on our cut line it's easy to slice away a couple of plies of the plywood cabinet side that intruded into the cooktop's space. As with most kitchens, the cabinets are assembled from several cases screwed together so each partition wall between cases is actually two thicknesses of plywood in dimension. Losing half or even 3/4 of one of them does no harm to the structural strength of the cabinets.

At above right we're finishing off a few chips of plywood and at below left, removing the last few intruders into the cooktop's below-counter space. I wanted to remove enough material to have working space to align the cook top precisely as desired on the countertop near the end of the installation process, and I didn't want any wood in direct contact with the cooktop's body.

Removing a slice of plywood to make the cooktop fit with adequate clearance (C) Daniel Friedman Removing a slice of plywood to make the cooktop fit with adequate clearance (C) Daniel Friedman

At above right you can see the cleaned-up space; we took care to vacuum up any sawdust and wood chips as well as to retrieve a roll of electrical tape someone had dropped into the opening behind the built-in oven years before.

Connect the cooktop's electrical power supply

You probably want to do this before hooking up the gas piping as the electrical wire and plug are simply plugged into a suitable grounded electrical receptacle (typically below the countertop and located there for this purpose). The power cord should be routed where it will not rub on any sharp edges nor obstruct piping nor obstruct the final lowering of the cooktop into its countertop opening.

Watch out: most likely the manufacturer of your gas cooktop will specify that the electrical cord must be connected to a properly-wired and grounded electrical receptacle. Do not modify the cord and no-cheating on the grounding connections.

Connect gas regulator & gas supply piping to the cooktop

Now it's time to check clearances and routing for the flexible gas connector tubing and to locate the gas regulator.

There was not room to mount the appliance gas regulator directly to the pipe nipple on the bottom of the new gas cooktop nor to install it on a street ell connected to the cooktop's gas input nipple. Either of those approaches ran into inadequate clearance from the top of the built-in oven below. Had there been no oven there'd have been no trouble.

Gas regulator connected to incoming gas piping (C) Daniel Friedman Preparing the gas cooktop gas inlet pipe nipple for installation of a flare adapter (C) Daniel Friedman

The installer of the old gas cooktop had run into the same problem.

Oh Joy! Look here: a gas regulator, already converted to LP gas and of the identical part number as our new gas regulator was already installed and connected atop the foundation wall in a niche where it just fit. (Photo above left).

Not shown was another gas shut-off valve installed lower on the interior of the foundation wall, but as this shutoff is inaccessible thanks to the built-in oven, it's the outdoor shut-off that is actually used in this cooktop installation.

At above right we are preparing the pipe nipple on the new gas cooktop to receive the flare adapter that will permit connection of the flexible gas connector tubing.

One end of the tubing will connect to the cooktop's gas inlet via flare adapter and the other end of the tubing has to connect to the gas regulator shown at above left.

Flare adapter attached to the gas inlet nipple on the Bosch gas cooktop (C) Daniel Friedman Gas connections for gas cooktop (C) Daniel Friedman

At above left you can see the new flare adapter being screwed onto the cooktop's gas inlet nipple. In this particular installation the flexible gas connector will be routed from the gas regulator to this flare adapter. In other installations the regulator might be connected to the gas inlet nipple and the flexible gas connector routed between the regulator's inlet end and the incoming gas piping.

Watch out: Be sure that the gas-rated pipe thread sealant covers all of the threads of the pipe nipple and fitting but do not use too much - we don't want to block the gas line with a blob of sealant.

Tighten this fitting taking care not to over-tighten and twist components up inside the cooktop itself.

At above right you can see that during connection of the flexible gas tubing to the flare adapter working space gets a bit tight. That's because we did not want to have to completely remove and later re-install the built-in gas oven below the cooktop. If we couldn't have made and tested the gas connections for leaks in the approach shown, we'd have had to remove the oven below to gain working space

. If needed

Tip: also inspect the flare fitting with care before installing it. A scratch on the flare fitting's mating face can result in a hard-to-find gas leak. For an example of just this sort of defect

Check the cooktop & piping for gas leaks

Check for gas leaks then turn gas supply back off (so if you break something during the rest of installation you may live to tell about it) At below left you can see the simple gas leak test used by most gas appliance installers: a spray soap solution.

Watch out: Be sure to spray this solution to thoroughly wet every gas connection. Be sure to inspect every gas connection for bubbles - those mean there is a gas leak to be repaired.

Gas leak test spray (C) Daniel Friedman Testing gas piping fittings for leaks (C) Daniel Friedman

At above right you can see the spray solution around the flare connection and in shadow, the threaded connection of the flare adapter to the gas inlet nipple. These connections and all of the gas piping connections must be tested for leaks. Use a flashlight, a mirror and an assistant to help hold parts out of the way as needed to be sure that your inspection is complete.

You might use a combustible gas detector to check for gas leaks also, but if that tool find a leak you may still have to go back this method to isolate it.

See more details about how to look for gas leaks

Watch out:  improper installation and even improper inspection and testing methods involving natural or "LP" gas can involve dangerous conditions and risk fire or explosion. If you smell gas you should leave the building immediately and should do so without doing anything that could create a spark such as operating a light switch or telephone. If the installing technician is unable to completely and immediately shut off the gas supply then from a safe location, call your gas company's emergency line and/or your fire department.

Install Cooktop Seals or Gaskets

Gaskets: Install any manufacturer-specified (and usually provided) gaskets or seals between cooktop and countertop surface. Bosch provides a thin foam gasket that is to be set about 1/4" in from the cooktop's upper surface outer edges before the cooktop is lowed in place.

If you are using clamps or supports that secure the cooktop to the countertop surface you may install them at this time. Keep in mind that if you detect a gas leak later you may need to remove these clamps to get access to piping for inspection or repairs.

Turn Cooktop gas supply back on

A quick trip back outside and a rapid dash back inside to check for leaks are your next exciting steps.

Gas line valve shown in the ON position (C) Daniel Friedman

Final Test for Gas Leaks at the Gas Appliance

Photo of a TIF 8800 combustible gas analyzer being used to check a kitchen sink drain for sewer gas leaksBefore securing the cooktop in place look, sniff, bubble test, or detector test again to satisfy yourself that there are absolutely no gas leaks.

Watch out: leaving even a small gas leak at any gas appliance installation risks a fire or explosion and fatal injury.

Shown at left: the TIF 8800 combustible gas analyzer, sniffing at a sink drain. This instrument is very sensitive. In fact a problem with using it to detect a gas leak at new gas piping installations is that it may be responding to the volatile organics emitted by the gas pipe thread sealant compound rather than to a gas leak.

That's probably why (other than being too poor to buy one) most gas appliance installers carry a bottle of gas leak detection fluid as we illustrated above.


Install the gas cooktop burner caps and grilles

You need the burner caps in place to perform the next step. If you like you can wait to install the grilles until after the final securing in place of the cooktop (shown later, below).

Final Check Gas Flame Quality & Igniters

Testing the gas burner flame and igniter function after installing the Bosch gas cooktop (C) Daniel Friedman

Turn on each burner one at a time and check gas flame quality and uniformity.

Don't let the burners run too long as you don't want to get burned on hot parts while finishing the last few steps in the job. The reason we make this test now before final securing of the cooktop in place is that if we find we need to change or fix something now is an easier time than after the cooktop is finally secured.

If you have trouble with uneven flame or igniter clicking check first for burner caps that are not properly seated. Gas burner caps askew or water or spillage into the burner are two chief causes of gas burner igniter trouble. If necessary

If the gas flame is uneven or color significantly off the air adjustment at the burner controls may be incorrect or worse, you did not install the proper gas orifice or spud.

See GAS FLAME COLOR CHECK if you need more deatils about checking the gas burner flame and the air mix.

Final Secure the Cooktop In Place

Bosch gas cooktop installed (C) Daniel FriedmanSet final cooktop exact final position and seal or secure of the cooktop in place on the countertop.

For this cooktop Bosch also provides screws and clamps that are used to secure the cooktop to the countertop from below, though fitting them in place can be difficult when space is very limited by a built-in oven below the cooktop.

Contrary to the manufacturer's recommendations and because we were precision-fitting the cooktop to just barely cover a too-large cutout (in the front to rear dimension) made by the countertop installer years ago, we added a small bead of clear silicone sealant around the edge of the cooktop where it meets the countertop surface.

This sealant, neatly done is not too ugly and it provided insurance against spills leaking beneath the cooktop where the too-large countertop opening meant that we could only use the Bosch gaskets on the two sides of the appliance.

In our photo above the board and cardboard shim at the rear of the cooktop are holding it precisely aligned in place so that our final steps at securing the cooktop will not have to be done over again. Obviously this board and shim are removed before the cook top is to be used.

Gas Cooktop & Gas Range Installation References


Continue reading at GAS APPLIANCE CONVERT LP-to-NATURAL GAS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.



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