Tankless Water Heater Repair Advice: this article explains concerns, problems, & special characteristics of tankless water heaters, also called instant water heaters or "on demand" water heaters.

Page top sketch of a point of use tankless water heater courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ].

Tankless Water Heater Problems & Defects

These questions and answers about tankless water heaters and how to troubleshoot and fix them were posted originally at TANKLESS WATER HEATER REPAIR GUIDE - so you'll want to check out that article.

On 2017-06-17 by (mod) - water heater lost power

Start at the fuse or circuit breaker period check for aluminium wiring, loose connections, or a problem brand electrical panel such as FPE

On 2017-06-17 by Anonymous

No power to box

On 2017-04-23 by (mod) - how to get the water valve back in place in the Bosch tankless water heater

rinka, here is an excerpt from the Bosch manual for your gas fired tankless water heater

Water Valve (Part # 8707002649): The water valve on this heater should be serviced periodically.

Lubricate component #23 on page 16 with a small amount of silicon, faucet or lithium grease every two years to keep its o rings fresh and pushrod sliding smoothly.

Every 3-5 years replace component #23 on page 16.

The frequency will depend on the mineral content of the water and conditions of use or whenever signs of corrosion appear at the gas and water valve joint.

Periodically check that the water inlet filter (#25 on page 16) is clean as well.

NOTE: If water valve is removed, be sure to also inspect the o ring seal on the end of the right hand side water pipe before re-installing. Lubricating the o ring with lithium or faucet and valve grease is recommended.

Here is a schematic showing the inlet water filter in a typical Bosch tankless water heater manual

inspectapedia.com/plumbing/Bosch-Water-Heater-Inlet-Filter-no-25.jpg

Be sure that the filter is rotated to proper position if it's notched or has a protrusion to locate it in place, and if necessary use a small amount of silicone grease to help it and tis gasket insert smoothly in place.

Here's the Bosch WATER HEATER MANUAL I consulted: inspectapedia.com/plumbing/Bosch-Aquastar-125-Tankless-Water-Heater-Manual.pdf
let me know if yours differs.

You can also call Bosch for technical support

Bosch Tankless & Heat Pump Water Heaters General Inquiries: 1-866-642-3198 Technical Support: 1-800-283-3787

or try this Bosch parts supplier

CONTROLLED ENERGY CORP. 340 Mad River Park Waitsfield, Vermont 05673 USA Phone 800-642-3111 Fax (802) 496-6924 www.controlledenergy.com Email: techsupport@controlledenergy.com

On 2017-04-23 19:14:17.497553 by Trinka Michalsonb

I took out the inlet water filter on my Bosch 1000 P and not I can't push the cap in enough for retainer pin to go in.

On 2017-04-05 16:40:47.835740 by (mod) -

Veronica

I was just this week discussing this concern of reduced water pressure from tankless water heaters with a local Bosch service technician.

I do not understand your surmise that "it can't be calcium buildup since I have no pressure" - on the contrary, it is exactly mineral scale clogging that occurs worst in tankless water heaters if the water supply is "hard" - high in minerals, and that can block the heating coil.

It may be possible to clean the coil using an acid wash, but if your water is hard the problem will recur unless you install a water softener - something I'd recommend.

But before ALL of that, do this test:

If cold water flow is strong at your kitchen sink tap but hot water flow is poor, mineral scale clogging is probably the culprit.
If both hot and cold flow are weak, check for a debris-clogged strainer.

On 2017-04-05 12:07:09.861895 by Veronica

I have a Rhinni tankless hot water, low hot water pressure can't use the shower, it takes over an hour to fill washer with hot water.

My water bill is about $3.00 I can't do dishes no pressure. It can't be calcium build up since I have no pressure. Have to shower at a friends house. If I had known this I would of put in a 40 gallon, water pipes were replaced,

On 2017-02-05 12:19:54.431836 by Anonymous

We have no hot water to our kitchen at all we had a ringing ru80i installed last year we have been trying ever since to get some help

On 2016-11-29 20:10:52.144983 by tucker

I installed a new dishwasher. When I start it, it does not trigger the on demand hot water heater. There is only the one hose hooked up to it which is the hot water.

On 2016-03-05 20:42:33.878019 by (mod) -

Ah. Didn't know that. Still sometimes it's necessary to flush and de scale a tankless water heater and or install a sediment filter or even a water softener, depending on the nature of the problem.

On 2016-03-04 12:37:04.558094 by Calvin

I have a tankless water heater so I don't think that will help me. Last night I replaced my brand new Delta faucet that was getting 0.5gpm with a new Kohler one that is getting 1.4gpm and that is working for now...

it usually takes 2-3 days for them to stop working so I'll measure it again in a couple days to see if its much less. Even if its 1.0gpm it will still be enough to turn on the tankless water heater.

On 2016-03-03 17:29:20.627612 by (mod) -

Calvin

We published a series of articles you'll find by searching the ARTICLE INDEX for WATER HEATER FLUSH PROCEDURE - take a look and let me know what questions remain

On 2016-03-02 by Calvin

Also forgot to mention, and this one really surprised me...

So with the NEW faucet I only get 0.5gpm out of it, with or without the aerator installed.

But if I disconnect the supply line to it, and run that straight to a bucket, I get 2gpm. So I assume the water pressure is just too low that it cant push itself out of a fixture.

How do I flush the system? Or you mean hire a plumber to do this? I don't think this is coming from the street since my cold water doesn't seem to have any sediment in it. And my hot water before I replaced the water heater didn't either. This just all happened after I installed the tankless.

I am wondering if maybe I turned my shut off valves on too fast after the install and the new water broke loose and eroded some build up in the pipes. The paint chip looking stuff though makes me think it came from my old water heater.

I even tried blowing it out with an air compressor by opening my tub faucet and blowing into the shut off valve on my kitchen faucet.

This got a little bit of sediment to come out but not much.

Also, none of my aerators are clogged with the debris.

On 2016-03-02 by Editor

Indeed low flow will shut off the heater to avoid overheating. I'd install a sediment filter at the point of water entry and also flush the system and bean shower heads, faucet strsiners, etc.

On 2016-03-02 by Calvin

I'm having trouble with one fixture, my kitchen sink, from getting it to kick on my tankless water heater that was recently installed.

When I first installed it, I had problems with all the fixtures, I'd have to open the bathroom sink while showering for example to get it to turn on the heater.

After my shower, I'd notice a lot of sediment in my bathroom sink. After a week of that nightmare, I tried it with my master bath and sink and a TON of sediment came out of my tub faucet. Since then, all the fixtures have worked on their own, except the kitchen.

I replaced the faucet with a new one, and that fixed it for a couple days, then I replaced the shut off valve, no buildup seen on the old one.

When I measure the flow rate of this faucet it is 0.5 gpm vs 1.5gpm at all my other faucets.

I tried blowing out with compressed air from the new faucet and out the detached water supply line, then reattaching and measure about 0.7gpm, enough to turn on the water heater, but again after a couple days it stops working again.

This is city water, the particles getting caught range in appearances from "sand" to what looks like paint chips.

On 2016-02-22 by (mod) - tankless water heater stopped completely

Carl:

1. check that the heater has power - this is an electric tankless water heater. Check for a tripped breaker or blown fuse.

If the fuse is blown probably there is a shorted heating element that needs replacement. Don't just turn it back on as that may be unsafe.

2. check the no-hot-water suggestions in the owners manual for your iHeat ADK series water heater as the manufacturer has some specific checkpoints.

If you don't have the manual, contact iHeat at Website: http://www.drakkenusa.com/ or Tel: 1-888-818-4328 or Email: support@drakkenusa.com

On 2016-02-22 by Carl Mathis

I have a Iheat -Magnum ADK M sires, it just stop getting the water hot. could you help me with this?

On 2016-01-25 by ALEC

I have a Eemax SP3512 electric water heater and it just quit heating the water. I CHECKED THE CIRCUIT BREAKER AND IT WAS FINE. Could you tell me what the problem could be. Thanks

On 2015-11-17 13:49:39.604441 by (mod) -

Syed I'd like to help but I don't' undererstand your system. If a water heater geyser is truly turned off then it cannot make hot water.

Perrhaps the water in your supply piping is being warmed by passage near another heat source such as a home heating system

On 2015-11-17 04:05:03.278126 by Syedhasnain123

My thankless water geyser burner does not get turned off I after the hot water tab is turned off.and thus hot water comes through cold inlet, I had already changed the magnet in the cold inlet but the problem still persists.tell me where lies the fault

Question: relationship of tankless water heater and frozen burst pipes

(June 28, 2014) Jenny kim said:
Hi, my name is jenny and i got burst pipe last winter with tankless heater.

I was out and the temperature was 30-28 degree in my area walnut creek california at that time.

When I came home, i found hor water pipe got burst on my roof and i got all waterdamage in every single room.

It was disaster. I contacted to insurance company, and company said, they won' t pay because pipe got frozen.
I have a question about tankless heater.

Hot water pipe is always keeping hot water inside with tankless water pipe?

How my tankless water hot water pipe got burst? Not cold water pipe burst before?
Because my hot water pipe got burst, so my house became sauna like three days.

I want to prove that my hot pipe just simply got burst because of pipe problem, not frozen.
Is any way that i can prove this tankless heater keep always hot water inside of hot water pipe?

Any one can help me? I got more than one hundred thousand damage, but insurance companh denied to pay it.
I will really appreciate it if anyone can give me advice, thanks!

Reply:

Jenny,

I'm sorry about the terrible water damage you describe.

Tankless heaters are normally "off" - they do NOT keep anything hot.

The design of tankless heaters causes a burner to turn on when water begins to flow through the heater. So no honest expert is likely to be able to help you prove that a heater was working in a what that it does not.

Of course you may have some other type of equipment installed that I don't understand from just your comment.

You will want to take at least these two steps:

1. review your insurance policy details with an expert, perhaps an attorney, to be sure you understand what coverage you actually purchased.

2. While I don't encourage people ever to rush into a dispute, you may need assistance from an independent insurance adjuster who can negotiate with your insurance company on your behalf.

The advantage is that such a person is expert on insurance policy coverage, laws, and in negotiation with the insurance company. The disadvantage is that the moment you consult an attorney or independent adjuster who is working for you, the relationship with your insurance company becomes adversarial.

On the other hand, if the insurance company is stonewalling you AND if you believe you were entitled to inurance coverage, you may have no alternative.

Question: Nortiz tankless hot water system freeze-ups

(Aug 12, 2014) Anonymous said:
looking for anyone with a problem with nortiz tankless hotawter freeze ups

Question:

(Oct 7, 2014) Ed Deane said:
No reading from Temperature Controller - front panel. There have been power outages in the area. Getting cold water - luke warm in shower but no hot water.
What is the problem.

I went through my gas provider for the install - their energy conservation program. They used a local outfit to install.

I noticed something else - usually HEAR

Reply:

Ed does the unit have power?

Follow-up:

Hi Dan,
I assume so. The fuse box shows no amp fuse being out.
Usually as I said - I usually hear the unit working - it's positioned in the garage - when my wife is upstairs running the water - the unit goes through it's operating cycle. That's not occurring.

Also, no reading from the Temperature Controller - front panel.
How would I know otherwise if NO POWER TO UNIT.

Reply:

Check the power circuit with a VOM or if it uses batteries, replace them with known good ones.

Listen for the igniters as well as checking the display.

Question: water heater ignites when not in use

(Aug 16, 2015) Rick said:
My water heater tries to ignite when not in use. can't figure out why.

Reply:

Rick

If a conventional water heater ignites only rarely it may simply be keeping the water at the temperature set on the heater's thermostat.

If a tankless heater is igniting there is a problem with a flow sensor, control, or there is water running somewhere that you haven't found.

The water heater burner should ignite when

- the heater is in use and temperatures drop due to incoming cold water into the heater

- the heater has not been in use for many hours and has cooled down enough to turn on the burner

A bad thermostatic control could also be at fault.

WATCH OUT: if the burner is not turning off when the heater reaches the cut-out or high temperature the system is unsafe, could explode and kill someone, and should be left off.

...

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  • TANKLESS WATER HEATER REPAIR GUIDE

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