Antique BDP Heat Pump--new tstat issue.

[georgelass]

Package heat pump.
BDP/Carrier
Product 542BU0030000PBAE (actually, first 0 is a greek phi, I think.)
Mod 542B030HP
serial 22/77/V/20227

I'm guessing it is a 1977, 35+ years old.

It had an old mercury bulb tstat on it and new tenants simply
wanted something modern and nice.

They wanted me to install a Honeywell they bought.
I did. Heating and cooling were fine.
However, when I turned the thing to OFF, the contactor
for the compressor & outdoor fan stayed on.

I tried a good Honeywell off my van. Same behavior.
Called Honeywell. They thought my contactor was merely stuck.

It wasn't. I didn't spend much time on it before it started raining on
me, but it appears the W terminal on the unit was energized. Y wasn't.
And that seemed to energize the the contactor, judging from its removal
de-energizing the contactor.

I don't remember seeing an O or B on the unit's terminal strip, so I'm
thinking W was the correct place for the reversing valve wire.

Of course, I don't have the wiring diagram. In hindsight, I should have
taken the wiring diagram to the dry and perused it there. But the rain
was gaining energy!

So if anybody has a wiring diagram or can help, I would be extremely
thankful.

Thank you.

[rundawg]

Package heat pump.
BDP/Carrier Mod 542B030HP

However, when I turned the thing to OFF, the contactor
for the compressor & outdoor fan stayed on.

It wasn't. I didn't spend much time on it before it started raining on
me, but it appears the W terminal on the unit was energized. Y wasn't.
And that seemed to energize the the contactor, judging from its removal
de-energizing the contactor.

So if anybody has a wiring diagram or can help, I would be extremely
thankful.

If you can get the mods to move this to the PRO forum, I'll post the wiring diagram.
I won't post manuals or technical info in this "OPEN" forum.

When the reversing valve (RR) is energized from "W", one of the two reversing valve relay contacts closes ("RR2" ), connecting "R" to "Y", to bring on the indoor fan.

That relay contact could be stuck closed, powering the contractor?

Sent you an email with the manual too.

[georgelass]

If you can get the mods to move this to the PRO forum, I'll post the wiring diagram.
I won't post manuals or technical info in this "OPEN" forum.

When the reversing valve (RR) is energized from "W", one of the two reversing valve relay contacts closes ("RR2" ), connecting "R" to "Y", to bring on the indoor fan.

That relay contact could be stuck closed, powering the contractor?

Sent you an email with the manual too.

If W closes RR, then RR2 gets closed, connecting R to Y which closes the compressor/OFM
contactor, regardless of whether the tsat energizes Y. That appears to be NORMAL
operation for this unit. Or am I reading this wrong?

I'm thinking that W should never be energized unless Y is also energized, that if I want
to make this thing work with a thermostat that has W always energized unless in cooling,
then I need to add a relay, power its coil with Y, and run W across the normally open
contacts so that W is energized to unit only if both W and Y are energized from the
tstat? I have never had to do such a thing before--modify a unit, but does that sound
like it would work?

Again, thank you, Rundawg.

[rundawg]

If W closes RR, then RR2 gets closed, connecting R to Y which closes the compressor/OFM
contactor, regardless of whether the tsat energizes Y. That appears to be NORMAL
operation for this unit. Or am I reading this wrong? That is the way I read it.

I'm thinking that W should never be energized unless Y is also energized, that if I want
to make this thing work with a thermostat that has W always energized unless in cooling,
then I need to add a relay, power its coil with Y, and run W across the normally open
contacts so that W is energized to unit only if both W and Y are energized from the
tstat? I have never had to do such a thing before--modify a unit, but does that sound
like it would work?

I'm thinking a heat pump thermostat that the reversing valve is energized in heating by hooking the "RR" relay up to the "B" terminal of the stat.

.

[georgelass]

"I'm thinking a heat pump thermostat that the reversing valve is energized in heating by hooking the "RR" relay up to the "B" terminal of the stat."

I'm pretty sure that IS the way it is with the two Honeywell thermostats that I installed.

But after thinking about it some more, I don't think I need to add a relay.
Instead, I think I can simply remove the RR2 connections, that enabling
Y when W is applied should never be necessary, since the thermostat is
always going to enable Y when it enables W.