Heat Pump Relay Maintenance / Replacement

[TBR]

2 Q:
Question 1:
Servicing Carrier Heat Pump 25HNA624 0030020.
Infinity thermostat displayed system "malfunction" needs service.
Trouble Codes: (all specific to 25HNA6) 75, 76, 77, 78 -- all related to "start voltage not achieved"
Not all together. Typically showing 75, 76 one day and 77, 78 another.
Cleaned out electrical compartment with compressed air.
The relay contacts show "camo type" discoloration. No evident pitting.

After blowing out the dirt and cobwebs in the electric compartment, the system is no longer identifying a malfunction and is running "normally".
Normal except that there are still intermittent days that trouble codes are being registered.
So I think the relays are on borrowed time.

From what I read on the site, relays are not cleaned but replaced but ...
- Is there a recommended spray cleaner to use on the relay contacts to extend life between replacing them? Or is a wear cycle a wear cycle and has nothing to do with outside cleanliness conditions?

What I have available locally is 'CRC Electronic Cleaner'.
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ALSO-
Question 2:
Looking at replacement parts there are obvious physical differences though operation specs look the same. Some reference back to my equipment and some don't.

The existing spec is:
#3100-15Q228 HN51KC024
VAC ------FLA --LRA -RES------Coil 24VAC
-------------------------------------50/60 HZ
240/277----30--150---40
480---------30---75----40
600---------30---50----40
... for which my understanding is the 240/277 line applies to this residential equipment.

White Rodgers makes a mfg# 94-388
VAC -------FLA--LRA -RES-----Coil 24VAC
-------------------------------------50/60 HZ
277---------30--150----40
480---------30--125----40
600---------30--100----40

Can someone pat me on the head and confirm compatibility from that info?

 

[shrtrnd]

I think most of us are hesitant to offer advice on HVAC because we don't know your level of expertise and would rather not
enable you to kill yourself or start a fire at your house.
You asked about the relay contacts. My limited experience with problems like you're describing is the Capacitors and Relays
are the most common culprits.
I wouldn't touch anything in there as long as it's connected to power, and you better not either.
Look-up 'burnishing' the relay contacts, there are small burnishing tools made specifically for that purpose to try to extend
the life of a relay. Frankly, considering the application, if you suspect the relay, I don't know why you wouldn't just replace it.
My recommendation is that you call out an AC guy to troubleshoot your system in the event you're barking up the wrong tree
and your error codes indicate some other problem you're not even considering by yourself.
Stay safe, and good luck with solving the issue.

 

[TBR]

I hear you. HIGH voltage. The coil needs to be discharged.
I have come to understand that the contacts on the relays of a condenser are not made to be burnished. I had the same idea but it is reportedly short term and replacement is in order. I was interested to know if anyone might have used a cleaner as part of regular maintenance.
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I could still use some hand holding on the part spec swap.