Want to Install an Unichiller Air to Water Heat Pump

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Old 12-01-07, 06:47 PM
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Want to Install an Unichiller Air to Water Heat Pump

Hi Folks,
Anyone have experience with air to water heat pumps? Looking to augument a radiant floor heating system with a heat pump. Currently the floor is heater with a Baderus boiler (oil) alone. Might like to change to 2 electric hot water heaters and apply the heat pump to it in the future.
One heating contractor came by to look over the job. He recommended a "Unichiller" (UNCHR 036 1 1 p )sounds like it's made for the system I have. But with the upgrades and an all around rebuild of the entire system the price was $20k. I have 2 houses on the present boiler, one at 1000sq. ft., the other 2200 sq. ft. Very pricey for me at $20k. I have experience plumbing radiant systems (2).
To top it all off the boiler is down (snowing outside, cold inside) and the boiler repair folks want $650- for a simple panel board controller. This is another story, I may post on it too. But the controller sits over the boiler and starts and stops the burners. Contractor says the 24volts needed to power the burner (a Beckett) isn't happening. It's the 120v to 24v converter he thinks. So replace the whole thing at $650. Any ideas for this prob?
Any thoughts on the Unichiller or your favorite unit? Where to buy such a thing too? My local plumbing wholesaler won't sell to me these days and I'm a contractor. Cabinets and interiors though.

Thanks, David
 
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Old 12-01-07, 07:23 PM
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What's the minimum temp limit on the heat pump?

Is the desire to replace part or all of the heat from the Buderus or is it supplement the Buderu or use off-peak?
 
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Old 12-01-07, 09:21 PM
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heat pump low temp effective to:

Who,
Thanks for your response.
This Unichiller H.P. works down to 42f. Below 42 I'd be using the oil boiler by itself. Here in Western Washington state that's ok, as we have pretty warm winters. Usually. Eventually moving to a couple of 220v water heaters as oil is getting expensive. So supplimenting, yes.
Geothermal may be too expensive. The land is big enough.

--D
 

Last edited by cascadesealion; 12-01-07 at 09:24 PM. Reason: spelling
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Old 12-01-07, 09:30 PM
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cascade, okay... yeah I was going to say if you were below range from where you'd get some COP factor to leverage the electrical that an electric boiler would be simpler...

I'd say solar would work for you about 2 days out of 50?
 
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Old 12-01-07, 09:43 PM
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Looks like my Honeywell aquastat is bad.

Any ideas on how to measure up and where to order a replacement? This thing is 16 years old.

Two days out of fifty, right, probably!

What's COP factor Who?

thanks, David
 
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Old 12-01-07, 10:07 PM
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David, is there no model number on your aquastat ? Sometimes it's on the back (use a mirror) sometimes on the inside of one of the side panels, sometimes a label inside the cover ... make sure you get the right one !

Can you download the manual for your boiler from buderus.com ? that should tell you what aquastat you need.
 
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Old 12-01-07, 10:37 PM
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It's the coefficient of performance or simply the multiple for the BTUs a heat pump can harvest as opposed to making the BTUs purely through electrical resistance heating. A kilowatthour of electrical heat through restistance gets you 3413 BTUs. If the COP is 3 for example, then a kwh gets you 3 x 3413 BTUs.
 
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Old 12-01-07, 11:13 PM
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Model no.

It's not a Honeywell. It's a Safgard Model 500. Who sells these units?

Thanks for the responses.
 
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Old 12-02-07, 10:25 AM
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If it's a Safgard 500, then it's not an aquastat at all ... that's a Low Water Cut Off ... and I can not imagine $650 to replace that... can you spell S-H-A-F-T ?

Try Google David...

I'll save ya a little trouble, here's the PDF for the Safgard:

500_600_700_

Hydrolevel 500 at P-S
 
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Old 12-02-07, 07:44 PM
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I picked up the wrong cover when last posting.......

Opps! It's an aquastat by Honeywell. I went through it this evening because the tech told me it was bad. "Not getting 24 v to the pump" he said. And for this Honeywell part to cost 650 is criminal. A super SHAFT job.
The aquastat seems to work fine. I bench tested it with 120v. I got 24v. at the thermometer side, 120v for the pump side and the integral switch seemed to work fine too.
Back on the boiler, reset into it's box it gives 120v to the oil pump. But there is no burn. The igniter isn't lighting up. Getting power to the igniter though. I pulled the iginter out but not sure if its adjusted right. The boiler did seem to run rough after tech's "tune-up". Wish I'd gone out to look it over before the thing finally quit.

Igniter info:
Allenson Ignition Transformer
CAT NO. 2741 TYP. No. 658 Date 0600
primary 120
secondary 10,000

How do you test 10,000 volts?! Can I wrap a narrow piece of tin foil for a one time test across the leads? Or? I have a tester but not sure about 10k! Should I expect to replace this igniter now? Assuming 0600 is 6/2000 & 7 years old?

Please let me know what you think as I've got to call the tech back Monday am so he doesn't bring the aquastat. I just wanted a decent tune-up
 
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Old 12-02-07, 10:16 PM
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You said "120V to the oil pump" ... do you mean 120V to the BURNER ? There IS an oil pump on the burner assembly, but I just want to clarify that part.

With the unit connected, and the thermostat calling for heat, you should see 120VAC on C1 and C2 , and 120VAC on B1 and B2 . Is that what you are getting ?

If you are getting 120VAC on B1 and B2, and that voltage is getting to the burner, what happens? Does the motor start ? Then, does it run for a little while and shut down ?

There is another control on the burner itself, called a primary control. That is a safety device that will shut the burner down if it does not detect a flame. Was the reset button pushed on the primary control ? What happened then ?

Do NOT keep pushing the reset control, as every time you do that, oil probably shoots into the combustion chamber, I'm just curious as to the sequence of events that transpired when the thing 'broke down'.

You said you "just wanted a decent tune-up" ... are you saying that it was working OK before you called the tech? and not working at all after he left ?

Honestly... to replace the aquastat, I could see maybe $400. There is gonna be a mark-up on the parts... there always is. Like those brake pads you can buy for your car for $20 at Auto-Zone, but you'll pay $60 at the shop... that's bidness... Unfortunately for most of us, there is no "Boiler-Zone" store on every corner. Yes, you can get an aquastat and easliy replace it yourself for about a buck and a half... but $650 ? no way.

NO! do not put your tester on that transformer, you will fry it for sure. There is a way to test it, but due to liability issues, I can't give you that info, sorry! I hope you understand.
 
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Old 12-02-07, 11:49 PM
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Liability? Here too?!!

Alright, no worries Tropp.

Thats right 120v to burner and pump. Motor starts, pumps fuel.I disconnected the pump to trouble shoot the igniter (so as not to flood out fuel). Push the primary control reset button and it (pump) runs but no flame. It was working great before the "tune-up". And worked for about 2 weeks after. Was popping a bit and not running well though.
Aquastats on ebay right?

HONEYWELL L8124A1114 AQUASTAT HIGH LIMIT RELAY L8124A

Mine is about like this unit now listed on ebay. A lot less than $650

So where to buy an igniter? Do you think date of 0600 is old? Should I just go ahead and replace it? Who do we call for this part? Ahh..... I see it on ebay too. $20- starting bid $9.50 shipping. Yup it's the 2741 658 Allanson is the correct spelling I suppose.
 
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Old 12-03-07, 01:38 PM
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Just called the major WA hvac parts distributor......

and they won't sell to me directly. Only selling to licensed HVAC contractors.

A tech is coming tomorrow. Someone from the same firm but who did tune up my boiler properly 1.5 years ago. I will be much better informed as he digs into the problem after having taken the systems apart/replace over the weekend. I just don't know how the check the igniter output 10,00 volts. And have no tools for setting the burner rich/lean settings.
I'm getting ready to hook up an electric hot water heater and purchase a good air to water heat pump into the system. An outfit on ebay has pool heat pumps and they are in my area. Currently building a relationship with them. Hope to get something better suited to residential hydronic heating.
 
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Old 12-03-07, 02:11 PM
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David, check out:

Patriot Supply

They have an eBay store too... sometimes items there are a buck or two cheaper than at their own website, and _most_ of the day to day items are there.

I've ordered LOTS of stuff from them, and they are most excellent. Pretty good prices, most of the time. Sometimes you can find cheaper, but their service is great. I usually get my packages in a day or two, but they are very close to me geographically. Yours might take a week...

Hopefully the different tech will be helpful... with all your new found knowledge though, try not to sound like a 'know-it-all'... that might put him on the defense, and you don't want that!
 
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Old 12-03-07, 07:40 PM
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Yeah my new found knowledge is pretty thin!

Have delt with this boiler for 16 years, but seem to forget knowledge of it when it needs trouble shooting every few years. Sage advice Trooper.

This tech is good, I liked him the first time.

Patriot Supply, ok thanks.

Any good tuneup tools/service kits you can recommend so I can do the annual myself? I'm not such a bad mechanic, can negociate my way around the Mercedes E320s and Ford diesel truck. With a little help from my friends
 
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