HVAC experts

[Platypus]

Well an update on this...

Had a different HVAC guy come out and apparently there's nothing on the heater itself.. he called it a 'toaster with a blowdryer on it'. All of the brains for controlling it rest in the thermostat. He replaced the thermostat with a completely different (nicer) and different brand and rewired the entire thing and it still does the same fucking thing. It turns on even when the room temp is the same, runs for a long time, shuts of for almost exactly 10 minutes and then repeats the cycle.

I'm getting really tired of this shit, can anyone shed some light please?

 

[AlienCraft]

Originally posted by: Platypus
Well an update on this...

Had a different HVAC guy come out and apparently there's nothing on the heater itself.. he called it a 'toaster with a blowdryer on it'. All of the brains for controlling it rest in the thermostat. He replaced the thermostat with a completely different (nicer) and different brand and rewired the entire thing and it still does the same fucking thing. It turns on even when the room temp is the same, runs for a long time, shuts of for almost exactly 10 minutes and then repeats the cycle.

I'm getting really tired of this shit, can anyone shed some light please?

Need make & Model, please.

 

[K1052]

Stop sticking your eggs in the vents to keep them warm.

 

[Platypus]

Originally posted by: AlienCraft

Originally posted by: Platypus
Well an update on this...

Had a different HVAC guy come out and apparently there's nothing on the heater itself.. he called it a 'toaster with a blowdryer on it'. All of the brains for controlling it rest in the thermostat. He replaced the thermostat with a completely different (nicer) and different brand and rewired the entire thing and it still does the same fucking thing. It turns on even when the room temp is the same, runs for a long time, shuts of for almost exactly 10 minutes and then repeats the cycle.

I'm getting really tired of this shit, can anyone shed some light please?

Need make & Model, please.

It's in my second to last post
Make/Model is a York(?) F2RP024H06G

 

[NoShangriLa]

If you must, then try jumping across the thermostat connections at the furnace to bypas t'stat, and force the furnace to run. But, I don't think t'stat is the problem.

My hunch is that the coil are freezing up due to extreme cold outside air and/or low refrigerant (if you have an outside/inside HVAC unit) therefore the highlimit shutoff the furnace every 5-15 minutes then reset (5 minutes default reset time) before it restart. The cycling continues till the furnace is repair.

The problem is that the HVAC outside unit was install to run in conjunction with stage 2 backup electric coils when it is colder than 97.5% standard season setting mark. And, this year is exception to the rule therefore the heat lost is greater than anticipated and the outdoor unit coils is freezing up because it is over worked.

The solution is to program/wire the system to lock out the outdoor unit once stage 2 electric backup run for a specific amount of time, if in that amount of time the heating demand isn't satisfy. Or, the better solution is install a outdoor sensor to lockout the outdoor unit during extreme cold spell.

If it is only a force air electric heater, then it could be that the highlimit or air-flow switch has malfunction.

That sounds like the opposite of my problem; it runs forever...

If the limit switch failed it could force the blower to constantly run due to t'stat call for heat & the heating elements are not satisfying the call for heat. It could also could be that 1 or more of the heating elements has failed. (This problem also can be associate with HVAC sys above).

 

[Platypus]

Originally posted by: NoShangriLa
If you must, then try jumping across the thermostat connections at the furnace to bypas t'stat, and force the furnace to run. But, I don't think t'stat is the problem.

My hunch is that the coil are freezing up due to extreme cold out side air and/or low refrigerant (if you have an outside/inside HVAC unit) therefore the highlimit shutoff the furnace every 5-15 minutes then then reset (5 minutes default reset time) before it restart. The cycling continues till the furnace is repair.

The problem is that the HVAC outside unit was install to run in conjunction with stage 2 backup electric coils when it is colder than 97.5% standard season setting mark. And, this year is exception to the rule therefore the heat lost is greater than anticipated therefore the outdoor unit coils is freezing up because it is over worked.

The solution is to program/wire the system to lock out the outdoor unit once stage 2 electric backup run for a specific amount of time, if in that amount of time the heating demand isn't satisfy. Or, the better way is install a outdoor sensor to lockout the outdoor unit during extreme cold spell.

If it is only a force air electric heater than it could be that the highlimit or air-flow switch has malfunction.

That sounds like the opposite of my problem; it runs forever...

If the limit switch failed it could force the blower to constantly run due to t'stat call for heat & the heating elements are not satisfying the call for heat. It could also could be that 1 or more of the heating elements has failed.

Wow this makes total sense and I believe you are right.

They installed the worst kind of HVAC for Chicago (it was negative 6F yesterday), it's an internal/external system that uses the AC in conjunction with the heater. The guy said the external component was damaged (on the roof) so he bypassed the AC completely when he rewired the new thermostat. Apparently that isn't the case?

Thanks again for your help, that makes a lot of sense.
BTW, since the new thermostat was installed, it no longer blows cold air at all, it just constantly blows hot heat during its operation.

 

[effowe]

Originally posted by: daveymark

the reason it "gets better" when you turn it off and back on is because it continuously will try to kick heat on for a limited number of times before it says "hey, there's something wrong with me, I'm going to shut down until you figure out what's wrong." so when you restart it, it resets the kill switch and starts the cycle over again.

what is the make and model? do you see a flashing light anywhere inside when it's on?

does it always blow hot air? without knowing more info it sounds like a flame sensor issue, try sanding the metal part with 100 grit sandpaper. be careful not to touch the ceramic/porcelain. then turn it off and back on again and see what happens. sometimes the flame sensor needs to be replaced too, and they are usually pretty cheap.

This is what it ended up being with my furnace. The heat would kick on for a few seconds then shut off. There were 4 blowers, one of which had the "heat sensor" in front of it. It's just a small (in diameter) piece of metal that's about 3" long. We undid a hex nut, sanded down the sensor to clean it up, and put it back. After we tried again the heat worked like a champ.

 

[Platypus]

I guess a more perplexing problem given the new info NoShangriLa posted is... why would the system keep running if I have it set to 74 and the room temperature is also 74? Shouldn't it shut off when it reaches the temp I set it at regardless of a system failure?

BTW, since the new thermostat was installed, it no longer blows cold air at all, it just constantly blows hot heat during its operation.

 

[NoShangriLa]

Originally posted by: Platypus
I guess a more perplexing problem given the new info NoShangriLa posted is... why would the system keep running if I have it set to 74 and the room temperature is also 74? Shouldn't it shut off when it reaches the temp I set it at regardless of a system failure?

BTW, since the new thermostat was installed, it no longer blows cold air at all, it just constantly blows hot heat during its operation.

Are you sure that it is set at 74?

Some t'stat controls have dummy settings to prevent the illiterate user from messing with the control. It possibly have internal control settings that have to be trigger before any changes can be made.

User may see 74F @ 74F setting on the display, but it may not be the correct temperature that was preset by the technician behind the scene

If you must, then get a good quality thermometer to check room temperature (may have some variant, and make sure that the thermometer is at the same place as the t'stat & height).

It blow cold was because the furnace blower was on with out heating elements running due to the heat call that initiate the outside unit to run (no heat just cycling indoor air), and after a certain (preset) amount of time the electric element kick in because the outside unit couldn't satisfy the call for heat.

 

[Rubycon]

If you have an outdoor unit (called a condenser if A/C and a heat pump if equipped with a reversing valve so it can provide heat in milder temperatures) that is malfunctioning it needs to be locked out and your thermostat set to use your supplementary (strip heaters) ONLY.

If wired with an emergency heat lockout relay just engage the emergency heat switch on your thermostat (heat pump thermostats will have this) and set to a comfortable temperature and it should work. If not, something is not wired correctly or there is a problem inside the air handler itself.

 

[Platypus]

YGPM Ruby

 

[NoShangriLa]

Originally posted by: Rubycon
If you have an outdoor unit (called a condenser if A/C and a heat pump if equipped with a reversing valve so it can provide heat in milder temperatures) that is malfunctioning it needs to be locked out and your thermostat set to use your supplementary (strip heaters) ONLY.

If wired with an emergency heat lockout relay just engage the emergency heat switch on your thermostat (heat pump thermostats will have this) and set to a comfortable temperature and it should work. If not, something is not wired correctly or there is a problem inside the air handler itself.

I belive that it is Emgergency heat is already adress by the tech when they installed a new t'stat. But, IMHO a new t'stat weren't needed because he only need to switch to E heat till the outdoor unit can be repair.

I don't think the wiring is the problem nor the indoor unit is the problem but more of a control issue, unless the elements has burnt out.

 

[Platypus]

Originally posted by: NoShangriLa

Originally posted by: Rubycon
If you have an outdoor unit (called a condenser if A/C and a heat pump if equipped with a reversing valve so it can provide heat in milder temperatures) that is malfunctioning it needs to be locked out and your thermostat set to use your supplementary (strip heaters) ONLY.

If wired with an emergency heat lockout relay just engage the emergency heat switch on your thermostat (heat pump thermostats will have this) and set to a comfortable temperature and it should work. If not, something is not wired correctly or there is a problem inside the air handler itself.

I belive that it is Emgergency heat is already adress by the tech when they installed a new t'stat. But, IMHO a new t'stat weren't needed because he only need to switch to E heat till the outdoor unit can be repair.

I don't think the wiring is the problem nor the indoor unit is the problem but more of a control issue, unless the elements has burnt out.

On that note, the tech suggested I use the E-heat option until he could come get it fixed but in that case the blower/heat/air ran constantly no matter what temperature I had the thermostat set to. I went back to the normal heat option because it at least shut off every now and then. What could be causing this constant 'always on' problem even in E-heat?

Unfortunately it appears this new thermostat does not have an E-heat button/toggle

 

[Rubycon]

Elements can burn out if the contactor sticks and causes them to run with lack of airflow. (this would even bypass the high temp snap disc!) An open high limit (snap disc) can also cause the same symptom.

If the G and R terminal are shorted together the blower will run all the time.

 

[NoShangriLa]

Originally posted by: Rubycon
Elements can burn out if the contactor sticks and causes them to run with lack of airflow. (this would even bypass the high temp snap disc!) An open high limit (snap disc) can also cause the same symptom.

If the G and R terminal are shorted together the blower will run all the time.

Blower can be set to run all the time, but home owner will feel cold air when heating elements aren't on due to cycling room air temperature only, such as summer setting on furnace sys with out AC.

Most open highlimit will force the blower to run as indicated in other AC/heat threads that you have seen me posted on (highlimit not necessarily be disc type).

Some systems blower are on timer (normally 5 min default setting) that run intermittently if the highlimit switch failed.

Are you looking to be working in HVAC?
Maybe you can come up here to Canada and be my apprentice

 

[Platypus]

Is there anything that can be done about the issue until spring? Is that just how the heat works on this system? The cooling works like I imagine it should.. I set a temp and it comes on when that temp changes in the room... thus far the heat has acted differently with two different thermostats.

 

[Rubycon]

Originally posted by: NoShangriLa


Are you looking to be working in HVAC?
Maybe you can come up here to Canada and be my apprentice

I'm friends with HVAC engineers on our ship and learn a lot from them as well as reading Althouse - cover to cover! Indoor environmental management is interesting.

 

[NoShangriLa]

Originally posted by: Platypus
Is there anything that can be done about the issue until spring? Is that just how the heat works on this system? The cooling works like I imagine it should.. I set a temp and it comes on when that temp changes in the room... thus far the heat has acted differently with two different thermostats.

It could be that the old t'stat didn't have the correct setting for E heat, or it lack the features. The new t'stat has been program to function with E heat mode till the outdoor unit is repaired/replace.

High SEER is the way to go, but personally I have only seen 21 SEERs.

It is very unlikely that you will need ducting mod because your home is already setup with heating & cooling duct work.