Spacepak loses 24 volts after brief power glitch, returns if 240 volt breaker cycled off/on

Jon_23

Have a Spacepak ESP-G air handler that works great, except when there are brief power glitches (power out for no more than a second or two). When this happens, the 24 volts seems to shut down (thermostat goes blank) and the only way to get it back is to cycle the 240 volt breaker off for a few seconds and then back on. Prior contractor added a PRO-24 '24V Circuit Board Surge & Spike Protection' that did NOT help.

Any thoughts before I purchase a new $400 control board? I feel like the control board may have been replaced in the past without fixing the problem. It is NOT the thermostat, as it has been replaced and there is no 24 volts to it after these power glitches.

Thanks. Jon

pecmsg

a safety’s shutting it down

https://www.icmcontrols.com/product/icm493/

Jon_23

Thanks. This makes sense. Jon

EdTheHeaterMan

This may just be the way that the ESP-G air handler control works. I wonder if an inexpensive time delay-on-break control would solve the issue?

https://www.supplyhouse.com/Packard-PTD203-Adjustable-Delay-on-Break-Timer-6-Sec-to-10-Min

My thoughts are that once the power is interrupted, the power restore time can be artificially extended with a time delay of 90 seconds or longer. This would also offer modest compressor protection, since the condensing unit contactor (which is powered by the ESP-G transformer) would have a short delay before being energized again.

It is a low enough cost to try it and get rid if it if it does not solve your problem. Lower than the cost of a circuit board i might guess.

Jon_23

I don't think this could handle the current I need. My air handler is on a 20 amp circuit with a FLA of 5.3 amps.

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1897342#Comment_1897342

Agree. this time delay can not handle the entire air handler load. I was thinking of only the transformer in your case. Here are 2 options. (click on the photo and zoom in)

EBEBRATT-Ed

The time delay is wired into the 24-volt circuit.

Although the power circuit is 240 volt the unit needs 24-volt power to start.

Next time before you reset the 240-volt breaker check to see if you have 240 to the unit.

Unless the breaker is tripping on the power failure resetting the breaker is not doing anything on the 240 volt side.

What you are doing is cycling the power to the 24 volt transformer and it is the 24 volts that is being reset

Jon_23

Thanks to all. This makes complete sense and should work. We will see shortly! Jon

109A_5

After a brief power glitch, you really should determine the actual state the unit is in before developing a resolution plan. Surge & Spike Protection devices do not fix power drop out issues.

Example; is the 240 VAC actually missing, is the 24 VAC at the transformer actually missing, is the transformer 24 VAC present and the 24 VAC between the R and C terminals missing, fault codes, etc.

pecmsg

@109A_5

Surge & Spike Protection devices do not fix power drop out issues.

The ICM 493 has High and Low voltage settings as well as phase imbalance and time delays all settings adjustable

Jon_23

Very good points. The problems are:

1. These outage incidents are rare (but annoying, especially if I'm away from the house). More common during 'storm' season when there are more power issues, but still rare. I can't seem to duplicate them by simply tripping/resetting the breaker quickly.
2. The air handler, of course, is in a very inconvenient attic that requires lots of work to get to (removing cloths from a closet…)
3. I really do need to check the voltages and faults after the next incident (assuming it is not at midnight with a house full of people getting very warm!)
4. Using an ICM493 will fix the symptoms as, with an appropriate delay time, it is essentially the same as cycling the 240 volt breaker (which does ALWAYS clear the problem).

pecmsg

2. The air handler, of course, is in a very inconvenient attic that requires lots of work to get to (removing cloths from a closet…)

Then how do you expect a tech to properly service it?

Jon_23

It can be accessed, but like many 90+ year-old houses, it was an afterthought. For a scheduled tech visit, I remove all the cloths, empty the closet, remove the closet rod, place a stepladder and pop the hatch (and it is then easy). The attic has the code required lighting, condensate pan, two pan drains, and the air handler is near the hatch.

It is just that storms and these power 'glitch' episodes never seem to happen at convenient times and dates. I was stating this just to explain why it isn't always easy for me to check the voltages and alerts after an episode.