Cruisair heat pump control system problem…I think

[Nick in Manitou]

Cruisair heat pump control system problem…I think

1984 53’ Extended Deckhouse

Using the old mechanical Honeywell T6052B thermostats.

Previous owner modified the boat pretty extensively and in the process removed the thermostat that I BELIEVE would have been in the galley. The galley and the v-berth systems run off of one compressor.

Current situation is that the thermostat in the v-berth is quite a mess with corrosion and is shot. When the system is turned on, it fires up the compressor and the seawater pump and delivers heat until it is turned off no matter what the thermostat is set to.

So I took the thermostat (Honeywell T6052B) from the master stateroom (where it controls heat and cooling as it should) and installed it in the v-berth to see if it would function there. In the v-berth it would turn on the compressor and seawater pump and supply heat when the thermostat was set to demand it, but when the setting was lowered so that it should call for cooling, no compressor or seawater pump came on. Shouldn’t it just be calling the same units to be turned on with the reversing valve not being called for?

The previous owner had a timer somehow replace the thermostat in the galley and perhaps that wiring there (which looks pretty sketchy and difficult to access) is the culprit. But I figured that I would ask the forum for any ideas of what to check next. I can understand a schematic to a certain extent, but since I don’t really know where to start looking, perhaps one of you folks can use the symptoms to come up with an educated guess as to what the problem might be.

I believe I read somewhere on the forum that the reversing valve is only powered in the heating mode, and we get heat out of the system when it is called for…so between that and the fact that the seawater pump is coming on in the heat mode but not the cooling mode, makes me think that there is a wire somewhere in the control circuitry that the previous owner probably cut. (I should mention that we live in San Francisco Bay and most people never need air conditioning. But if it is on the boat I want it to work if possible!)

I know that folks think the newer controls are great, but for now I am watching my wallet and would rather make sure that the system can work before I spend the money for the fancy digital controls.

If anyone has one of the old Honeywell T6052B thermostats around that they don’t need, I am looking for one! (Even if it is just to control the heat in the winter!)

Thanks!
Nick

 

[miboatnutz]

Re: Cruisair heat pump control system problem…I think

I have same boat same year.

The thermostat in the v berth controls forward cabin and galley. I just had a Honeywell thermostat go bad in the master stateroom. Purchased two brand new thermostats on eBay for $35.00 each. They were new old stock from some HVAC company.

There were actually several more listed so you might get lucky. I just did a search on Honeywell and the model number and about a half dozen were listed for sale. That was four months ago.

 

[miboatnutz]

Re: Cruisair heat pump control system problem…I think

Only HVAC controls in the galley are fan blower speed rotary switch (low to high) located just below the vent grille.

 

[Nick in Manitou]

Re: Cruisair heat pump control system problem…I think

Brian (Miboatnutz),

Thanks a lot for the suggestion about eBay for the thermostat. I thought I had looked on the web a few months ago and not found any replacements at a reasonable cost, but at your suggestion I tried again and found a seller on eBay who had 2 new thermostats for $30 each including priority mail shipping!

I ordered one - although I was tempted to pick up the other one too at that price!

Re my thought that there might have been a thermostat in the galley originally: The system drawing for the air conditioning (Figure 3,10) that is in the manual that came with the boat shows a thermostat in the galley...although the schematic ("Air Conditioning Wiring Diagram" CN130-ED) does not show one in the galley.

But if no one else has a thermostat in the galley along with one in the v-berth, that should make figuring out what my problem is a bit easier...maybe.

So now, why would the compressor and seawater pump come on when calling for heat but not when calling for cooling?

Nick

 

[SKYCHENEY]

Re: Cruisair heat pump control system problem…I think

I don't know why you mess with this old stuff. I replaced my themostats and PWX control boxes years ago with Coastal Climate Control FX1 and have not had a single problem ever since. They are cheap and the temperature swing between cycling on and off is much tighter. That Honeywell thermostat setup was not used for too long before they came up with something better.

 

[Nick in Manitou]

Re: Cruisair heat pump control system problem…I think

Sky,

The newer controls (FX-1, FX-2) look to cost $399 to $597, and before I venture into that sort of expenditure I would want to make sure that the system is completely functional.

I would hate to spend the money for new controls and find out that it is time to replace the entire unit!

Nick

 

[Nick in Manitou]

Re: Cruisair heat pump control system problem…I think

Just wanted to follow up on my statement that I had found a new old stock T6052B Honeywell thermostat on eBay.

I did find one that was supposedly for sale...but the seller never shipped it and did not respond to messages from me or eBay. EBay is refunding my money...but what I need is the thermostat!

The same seller (Livingthedadslife) still is advertising one of these for sale, but I wouldn't think he actually would follow through with selling that one when he didn't bother shipping the one I had paid for.

If you have one that is functional that you would part with, please let me know.

Thanks,
Nick

 

[jim rosenthal]

Re: Cruisair heat pump control system problem…I think

You might try mcmaster.com or wwgrainger.com. They might either have a NOS one, or be aware of a substitute item that would do the same things.

 

[SKYCHENEY]

Re: Cruisair heat pump control system problem…I think

Sky,

The newer controls (FX-1, FX-2) look to cost $399 to $597, and before I venture into that sort of expenditure I would want to make sure that the system is completely functional.

I would hate to spend the money for new controls and find out that it is time to replace the entire unit!

Nick

Move a known good thermostat from another unit to make sure everything works.

 

[Nick in Manitou]

Re: Cruisair heat pump control system problem…I think

Sky,

One of the reasons I am holding off installing a different type of thermostat at this point is that I did try moving a known functional thermostat from the master state room into the v-berth to see if the thermostat was the whole problem. It was not.

With a thermostat that works fine in another part of the boat, the system in question does not call for the compressor or the seawater pump when in the cooling mode.

I am going to be ringing out wires to see if there is a discontinuity that is causing the trouble.

I was hoping that perhaps someone on the forum would be able to tell me that the problem must be with wire 'X' which calls for cooling from the thermostat.

Can anyone tell me which wires on that thermostat provide what function?

Thanks,
Nick

 

[SKYCHENEY]

Re: Cruisair heat pump control system problem…I think

Sky,

One of the reasons I am holding off installing a different type of thermostat at this point is that I did try moving a known functional thermostat from the master state room into the v-berth to see if the thermostat was the whole problem. It was not.

With a thermostat that works fine in another part of the boat, the system in question does not call for the compressor or the seawater pump when in the cooling mode.

I am going to be ringing out wires to see if there is a discontinuity that is causing the trouble.

I was hoping that perhaps someone on the forum would be able to tell me that the problem must be with wire 'X' which calls for cooling from the thermostat.

Can anyone tell me which wires on that thermostat provide what function?

Thanks,
Nick

Its in your Hatteras wiring diagrams. I had mine out last when I wired the FX1.

 

[Nick in Manitou]

Re: Cruisair heat pump control system problem…I think

Actually, Sky, I did just that.

I spent today trying to nail down the problem. I started by trying to see if there were any wires that had discontinuities between the thermostat and the PWX box. I didn't find any...

So I dug out the wiring diagrams and was trying to make sense of what I was looking at. I could see a few places where the colors of the wires didn't agree with what was on the diagram, but in one place it looked as though two wires had been swapped. I changed them back to what I saw on the diagram and the system worked (with the one good thermostat I have)!

I believe that the previous owner must have just moved things around trying to get heat out of the system despite the failed thermostat. He put in a timer and set it up so that if the timer called for the system to be on, the system turned on the heat. (Winter - San Francisco)

So, now I know that the system will do what it should with a good thermostat! Since the budget it tight at the moment, I will continue to look for a good (cheap) Honeywell T6052, but may move into the modern age when $$ allow.

Thanks,
Nick

 

[SKYCHENEY]

Re: Cruisair heat pump control system problem…I think

Nick,
Glad you figured it out. If you do go with the FX1, you can remove the PWX box completely and not have to worry about traics and triggers anymore. You can also vary the fan speed and dehumidify and all of that good stuff.

You'll also have spare parts for the other units if you only upgrade one unit at a time.

 

[Nick in Manitou]

Re: Cruisair heat pump control system problem…I think

All,

As we are still under budget constraints, I have found a NOS Honeywell T6052B thermostat on eBay and installed it. Although it was more expensive than I had hoped, it was still much less than the newer digital controls (that would have been nice to go with).

So, at this point we have the ability to heat and cool...both of which we have needed here in the San Francisco Bay area in the last week!

Thanks for all the help and suggestions.

Nick

 

[SEVEN]

Re: Cruisair heat pump control system problem…I think

Post a picture Nick.

 

[Nick in Manitou]

Re: Cruisair heat pump control system problem…I think

Rusty (SEVEN),

As you requested, I am posting a photo.

The new thermostat, installed, and the old (very dead) one leaning against the wall below it.

I don't know what happened to the old thermostat, or where it was when it happened, but the inside looks even worse than the outside does! The panel it was attached to when we purchased the boat looks fine.

Now the system works as it should, but I can't say that I don't feel that the FX1 would be an improvement. (Double negative equals positive, right?)



Nick