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Recent heating system repair Q&A

Heating system installation, repair, maintenance questions & answers set #6

Q&A on how to troubleshoot & repair heating systems in buildings.

These heating system articles answer questions about all types of building heating systems and describe how to inspect, diagnose, and repair heating system problems, how to cut heating bills, and heating system safety, heating system efficiency and heating trouble-shooting advice.

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Heating System Q&A Set #6

Smith cast iron boiler data tag information (C) Daniel FriedmanThese questions & answers about troubleshooting heating systems in buildings were posted originally at HEATING SYSTEMS - home - that's a great place to start finding diagnostics for your heating system type and its problems. aces, and other equipment.

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On 2018-04-27 by (mod) - accidental hot water circulation

I'd be surprised that the thermostat would not act "fast enough" it the thermostat is actually working at all and assuming it's properly located.

I'd also check that you're not circulating boiler water through the heat exchanger involuntarily, such as can happen if there is a defective zone valve or check valve that doesn't close when it should.

On 2018-04-26 by Don

The thermostat is the first thing I checked. It is working properly. The stat pulls a relay which turns on the fractional hp pump and opens the zone valve at the boiler. Zone valve end switch makes and pulls another relay which turns on whole house circulating pump and fires the boiler. The water from the boiler is less than 200 since that is what the limit is set to.

The 1" pex supply line to the heat exchanger is about 50' away from the zone valve, however the valve is on the return side and I would think there would not be any hot water to the heat exchanger if not calling for heat, however, the supply side at the heat exchanger is usually very hot.

Could it be the water temp is so hot and the rate of rise, temp, is faster acting than the thermostat? You said not the right model. I bought it thru a pool/jacuzzi supply house. I have tried two models to no avail.

On 2016-11-23 by Pete d.

My gravity feed hot water boiler with a republic gas conversion unit works great...but recently it developed a weird problem! It woos he's quite loudly when it shuts off!like a huge back pressure or something!I need help!

On 2016-11-03 by John

Are transite flue boxes OK to use?

On 2016-11-02 by Tom

I need to move my oil tanks. In doing so, the fuel line will be close to the electric dryer vent. Is this a problem?

On 2016-10-23 by bob

As the heading says I bought a used Goodman GMP 100-4 and the red light on the board blinks 4 times. As soon as power is turned on tho the Furnace I hear a click and a few seconds later the blower motor and inducer run even with the thermostat disconnected. I have checked the inductor switch and have continuity, and also tried jumping it.

I checked the nipple on the inductor and it is clear, the hose is not kinked. The vacuum pot does open and close when vacuum is applied. the fuse on the board is good.

I did not see a reset button any where. Also there is a multi connection plug laying in the bottom of the Furnace and I have no idea what it is for. See photo I just happen to think I have not checked the igniter. It will do the same with the thermostat connect or out of circuit. Am I missing something, is the board the problem.

On 2016-09-06 by Joey - Running pex tubing

I currently have a single zone monoflow Tee system in my home. I would like to make this into 4 zones (1 zone per level of home) what would be the easiest way to achieve? I was thinking of installing as follows:

Running pex tubing and crimping onto the 1/2" lines that go to each convector (where possible, mostly the basement allows for performing this for the MBR kitchen and living room) in series with 1 return, however I have been reading a great deal about series loop systems and what I have been seeing is they are antiquated? your thoughts on this (currently have convectors in all levels of home)
Joey

On 2016-06-01 by (mod) - age of a Mini Gas boiler f

It's encoded in serial number. Search InspectAPedia for HEATING SYSTEM AGE to read details

On 2016-05-21 by noel murphy

How does one determine the age of a Mini Gas boiler from the data plate information ?, Thank you, Noel

On 2016-03-03 by (mod) -

Re-posting from old copy of this web page:

AUTHOR:Christy Trotter (no email)

COMMENT:My furnace keeps coming on and off very frequently. How can I check my thermostat to see if it's working properly??

On 2016-02-29 by (mod) -

Bill, thanks for this field report on how you replaced a Taco circulator pump.

I'll copy the post over to our article on circulator pump repair for noisy circulator pumps - see https://inspectapedia.com/heat/Circulator_Pump_Noise_Repair.php

On 2016-02-28 by Bill - replacing my Taco 007-F5 Circulator

Sharing my recent experience in replacing my Taco 007-F5 Circulator. Perhaps it will help some fellow DIY’ers.

Existing Circulator started making noise. Decided to replace the entire unit. Reasons:

(1) while possible to replace just the cartridge cost is ~ 80% of the entire unit,

(2) current install used the flat red ‘rubber’ flange gaskets and they had hardened up and

(3) there was some noticeable rust around the flanges.

So for less than $100 had new Circulator + new Bolt Set with the flat red flange gaskets.

Note: the new Taco’s come with the ‘square’ rings, not the rubber gasket. And they do not come with new bolts. New pump also has square ring grooves in the flange face to accept the rings.

In researching found out that Taco changed to square ring due to fact that the red gaskets can ‘take a permanent set, and with the materials expanding and contracting, Taco decided to change over to the o-ring type…’

Square rings it is.

Disassembly straight forward and not covered here.

Clean up of boiler / pipe flange faces was accomplished with scrapper, wire brush and finally, do to some heaver scale, with an electric palm sander with 100 grit. Cleaned and until nice and shiny but still had some very minor pits, and right on the surface where the square rings would seat. Stuffed small rag into pipes during cleaning to keep out debris. Don’t forget to take out!

Found lot of comments about using gasket sealant and how much to torque the bolts. Here is what I did.

I decided on Permatex non-hardening form a gasket due to a concern about the small pitting on the boiler flanges. Used “a small dab will do ya’ on the side that seats into the Circulator, spun it around a turn or two to evenly spread.

Then set up for install but putting one side’s flange bolts pushed thru the boiler flanges. Idea is that will put a thin film of sealant on the square rings and need to get installed quickly before it sets, so with one side bolts sticking thru, can slide on the Circulator, stick thru the other bolts and it will stay put while you put on nuts , align and tighten.

Note about the nuts. These are against the Circulator flange that is a ‘slot’ not hole. So I used washers under the nut (not bolt) because I believe it will help spread the clamping force better. Or perhaps I am just set in my ways and bolts need washers under.

For torqueing the bolts, did not use a set value. Instead I heeded the advice I found that aligned with my own experience that says in part: ‘one of the main design features of the thick square section ring gasket is vibration isolation, but if you crank it down until the flanges almost touch you lose that function plus you distort the gasket and it is more likely to leak’.

I tightened down the boiler side flange first since its flange is hard mounted so to speak. I tightened the left side nut a little, then the right side a little, back to the left side, etc. I made sure the gap between the 2 flange faces was even and had a visible gap. I ended up with about 2 ½ threads showing and I measured the gap at ~ 0.056” Then did same on the pipe side.

Note: since it is more of a “snugged up” then torqued down, I did use Blue Threadlocker.

Filled it back up, fired it up and just perfect. No leaks.

On 2016-02-23 by (mod) -

Maggie,

You might want to ask a professional, like an electrician, to monitor all of your electrical circuits to see where the usage is occurring. It is possible that a current leak, or bad motor or something else is at fault.

On 2016-02-23 by Maggie

I have had oil heat for 4 years. I am surprised at the huge increase in my electric bill during heating season

. I have read that oil boilers do no use much electricity, but my electric bill more than doubles during heating season. That is significant in my opinion. Is that normal?

On 2016-02-13 by (mod) - Start by checking for shorted thermostat wires.

Stewman

Start by checking for shorted thermostat wires. Search InspectApedia for HEAT WON"T TURN OFF for detailed help

On 2016-02-13 by (mod) -

Matthew thank you so much for the email problem alert. Indeed our email, hosted at Godaddy, had filled our mailboxes and mail was being rejected. I needed to set up an automatic purge of old mail. It's fixed now. You sure helped us out.

Daniel

On 2016-02-13 by stewman

goodman aruf363616AA split system. My heat will not cut off unless the shutoff at breaker. Whats the problem or how do I troubleshoot?

On 2016-02-08 by (mod) -

If your oil burner is not running you need service/repair; possibly sludge or air in the system needs to be removed - a common occurrence following running out of oil.

If the boiler runs but radiators don't heat the problem is something else: search InspectApedia for COLD RADIATORS to see diagnosis and cure

On 2016-02-08 by pat speight

I ran out of oil+didnt realise got a fill while ago but rads not working still?

On 2016-02-06 by (mod) -

Hi 180-200

Lo 20 or more degrees lower than HI

Search inspectapedia.com for

AQUASTAT SETTINGS

for complete details

On 2016-02-06 by Lonny

what is the tempature settings , high and low on a hot water boiler system ?

On 2016-02-02 by Ryan

I have a an older forced water baseboard system. I purged the air out of the first floor (zone 1) baseboard heaters and it got rid of the knocking noise. I also did the same for my 2nd floor (second zone) but now I am not getting heat on the 2d floor. I can hear water trying to get up there but nothing.???

On 2016-01-18 by jeannie

It's 11 degrees outside and my furnace wants to keep running. I'm getting scared. What do I do. I'm on very low income with a child in the house.

On 2016-01-17 by Paulette

The furnace was not working. They came and pushed the reset button, cleaned it and replaced a copper wire that brings the oil to the furnace. It worked for a few weeks and has shut down again. I have pushed the reset button but the furnace will not remain working for more than 15 seconds.

The person cleaning it has never seen this type of older furnace before and I do not have confidence that he will fix it if I use his service again. Any suggestions? It is a Lenox J-533723, Burner OHP31-10 with a model number of OF7-189S.

On 2016-01-05 by (mod) -

Bob,

Sorry but I don't quite understand the relationship between asserting a heat exchanger is cracked and the condensate that was observed.

Certainly there are heat exchanger test procedures using tracer gases that can detect a leak even when the actual damage is not visible. If you go ahead with the repair, I would want to see the old, removed-heat exchanger and to have the damage pointed out.

On 2016-01-05 20:03:40.775827 by Bob Altvater (bubbavaterman@gmail.com)

Recently had my furnace inspected/cleaned and the technician said that my secondary heat exchanger was cracked and needed to be replaced.

He showed me some condensate under what looked like a drip pan. Obviously, without removing the heat exchanger there is no way to see or find a crack.

Does the condensate drop into a dip pan on its way to the drain line ? Should there be visible liquid visible ?

On 2015-12-29 by (mod) - tell me whether cadet heaters feb092001 and sep262005 have been recalled?

Sure see

https://inspectapedia.com/heat/Cadet_Encore_Heater_Recall.php

and

in that article you'll see also links to two CPSC documents with recall details in PDF form

On 2015-12-28 by Anonymous

Can you tell me whether cadet heaters feb092001 and sep262005 have been recalled? Thank you

On 2015-12-21 5 by (mod) - problem with a boiler that runs when no heat is being called for

Thanks Dave.

To be clear, as this is a problem with a boiler that runs when no heat is being called for, Perry should disconnect wires AT THE BOILER- that way we'll know if the problem is the aquastat, a relay, or another control.

On 2015-12-20 by dave

if your furnace is firing then I would check the fan limit switch. dicconect both wires and put together with electrical tape or some time push together. Turn furnace on to heat and set temp. if all r=works proper then the limit switch needs replacing.

On 2015-12-04 by (mod) - boiler and pumps run all the time even if the stat isn't calling for heat

Perry see this article and let me know if you have more questions

https://inspectapedia.com/heat/Thermostat_Stuck_On.php

On 2015-12-04 by Perry

I have a boiler and the pumps run all the time even if the stat isn't calling for heat

On 2015-11-17 by (mod) - blower won't turn on

Sounds as if the furnace burner itself is not igniting.

On 2015-11-17 by Vincent

AUTHOR:Vincent (no email)

COMMENT:Hi. When I first started our heater this winter (fan - auto, system - Heat) as I adjust the temp up, I can see on the panel an arrow on "system on" appear. I waited for a few minutes to hours but blower won't turn on. Then randomly, blower turned on but air is cold. Then it would stop after a few minutes.

I did test and set the fan - ON. Blower (cold air) turns on. Then I would set the system - HEAT, blower still on.

Raised the temp setting up, as soon as the panel says "SYSTEM ON", the blower will turn off. This happens on both TStat (connected thru a 2-zone hvac controller). When set to "COOL", blower responds normally.

What do you think is the issue. Thanks in advance.

On 2015-11-14 by (mod) -

I am not confident but I agree the txv could jam.

On 2015-11-13 by RemodelA

Hey Mod, since my last comment ( and before I read your's ) and before I run down the road naked, screaming obscenities. I checked the pressures.

When I switch to heat, the low side goes up a little ( from 60 to 70 PSI ) BUT the high goes from 150 to like 300 a climbing before I got scared and shut it down. Any thoughts? ( TEV TXV ? ) AND thanks again. ANDY

On 2015-11-12 by (mod) -

A bad control board or relay or a bad outdoor temperature sensor

On 2015-11-12 12:56:39.317900 by RemodelA

Thanks Dan J I doubt the compressor is bad ( works well in cool ) And it heats fine in Aux heat mode. Just in Regular heat ( Heat pump mode ) it trips breaker. Shouldn't the aux heat cycle in reg heat mode ( at the large temp difference ) and what could make it stick on?

On 2015-11-11 by (mod) -

Jack:

Usually what you describe is traced to blocked hot water flow due to an air-bound system or heating pipe loop. Search InspectApedia for AIRBOUND HEAT to read details.

On 2015-11-11 by (mod) - heat pump trips breaker in heat mode

Remodel

It sounds to me as if your system is stuck in aux heat mode - it's double-heating.

Also check the current draw of the compressor as you could have a failing compressor motor.

On 2015-11-11 by jack j

Getting lot heat to one bd rm, first on line, but little heat rest of house on loop. Water hot back to circ. Pumps.
No air in line. Can You figure this out for me. ????

On 2015-11-11 by RemodelA@aol.com

Have an old package heat pump unit installed with electric auxilary heat.

Cools fine, heats fine in AUX heat mode, However, in regular heat mode the unit runs some 10 - 15 minutes then trips the breaker.

I tried amping-up to a 40 amp with the same results.

A big trick is the air exchange going in at 55 and coming back in at as high as 120 degrees

. I think must be some thing should make the heating coil switch on & off and is not working. Am I thinking right? And if so, what would that thing be called and what would it look like where would it be. Or if I'm thinking wrong what else might it be? ANDY

On 2015-11-07 by (mod) -

CME you need to determine if the thermostat is 24VAC (standard indoor thermosats) or a 120V "line voltage" thermostat - then you can buy any simple thermostat and it will do the same switching. Using a light switch would not be economical.

On 2015-11-07 by cmetoneill

I live in an apartment building that was built in the late 1950's or early 60's.

The building is heated by a hot water boiler system. There are thermostats in each apartment that control either a small electric circulating pumps or maybe just a valve. Currently the thermostat installed acts only as an on/off switch which could be replaced by a light switch. I would like to find a thermostat that will work with this.

Which thermostat would you recommend? Is additional information required to answer this question?


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