277 single phase single pole to, 208-230 single phase 2 pole

[augie47]

this might help
http://static.schneider-electric.us...ge Transformers/Buck and Boost/7414CT0201.pdf

 

[mon6am]

I am tring that rought also but as of now no not yet. They are not making comerical heat pumps that small for a few months and I cant wait that long.

 

[mon6am]

I guess another concern is that there is the controls use a 120v to 24v transformer.

 

[augie47]

I guess another concern is that there is the controls use a 120v to 24v transformer.

That puts a fly in the ointment. Very unusal from mt experience. All the ones I have seen had a 240/24 control transformer.
In that case, a buck & boost would not be your answer.

 

[winnie]

1) Do you have a good hvac guy that you are working with? It doesn't sound like the new heat pump that you are considering is that much smaller then the one that is 'oversized'. Given the incorrect sizing at the start, do you have correct sizing now?

2) Are there options on the control or output side that could be used to eliminate the problem, for example could additional thermal mass (phase change material) be added to the system to reduce the temperature swings? Could the current system tolerate a variable speed drive to controllably adjust the cooling capacity?

-Jon

 

[LarryFine]

I guess another concern is that there is the controls use a 120v to 24v transformer.

If you need 120v, you'll need to use a 'real' transformer, not a buck-boost.

 

[Smart $]

I guess another concern is that there is the controls use a 120v to 24v transformer.

That puts a fly in the ointment. Very unusal from mt experience. All the ones I have seen had a 240/24 control transformer.
In that case, a buck & boost would not be your answer.

If you need 120v, you'll need to use a 'real' transformer, not a buck-boost.

While true, I'm with augie in that my experience has 230/208-rated equipment never having a 120 x 24V control transformer (though it may have a "universal" multi-tap control transformer which just happens to have a 120V tap/option). Besides, wouldn't the nameplate/spec's have to call for 120V also?

 

[benaround]

I'm with Jon, just slow the existing supply fan down.

 

[mon6am]

I looked at the control transformer and it is a multi tap. however it has a commom and one lead for each voltage so wouldn't that still be 120v to common.

 

[mon6am]

What i am understanding is, that I wire the buck-boost from 277v primary to 230v or 208v secondary, I will have one leg that will be lets say 230v and a neutral . From there I wire the contactor of the heat pump L1 would be the 230v leg and L2 would be the neutral and make sure the control tarnsformer is wired for 230v. The control transformer has a common and one orange for 230v, so I would wire common to L2 neutral side of contactor and orange to L1 or 230v side of contactor.

 

[LarryFine]

I looked at the control transformer and it is a multi tap. however it has a commom and one lead for each voltage so wouldn't that still be 120v to common.

No. As with any load, the voltage between the two supply conductors is all that matters.

If there is, say, a white common wire (or a com. terminal), black, red, and orange wires (or terminals), then use the common and whichever wire or tap matches the supply voltage.

Again, it does not matter which, if any, wire is grounded; only the voltage between them.

 

[Smart $]

What i am understanding is, that I wire the buck-boost from 277v primary to 230v or 208v secondary, I will have one leg that will be lets say 230v and a neutral . From there I wire the contactor of the heat pump L1 would be the 230v leg and L2 would be the neutral and make sure the control tarnsformer is wired for 230v. The control transformer has a common and one orange for 230v, so I would wire common to L2 neutral side of contactor and orange to L1 or 230v side of contactor.

Sounds good to me

 

[mon6am]

Thank you everyone for all the help!!!!!!