My geothermal compressor just died.

[davesl708]

I have a Waterfurnace ground loop geo system. 22 years old so I feel like I'm on borrowed time with the unit! Only problems I've had both occurred last winter when I had to replace blower motor and flow center (not the pumps, but the console). What a shame to have to deal with your compressor going kaput after 11 years.

For what it's worth, I'd seriously consider the 30% federal tax credit for new geothermal installations through the end of 2016. It has to be a new geo installation, but replacing an existing geo system still works. Here's a link to details: 30% Tax Credit Geothermal Heating & Cooling Install - 2015 Geo thermal

I'll probably go ahead and install a new system during this year to take advantage of the rebate.

I installed the Waterfurnace system in 2011. Took advantage of the 30% which made it comparable in price to the high end gas/electric systems.
Paid the extra to have the wells drilled rather than ground looped.
Well worth looking into. I don't miss that noisy outside unit and love the very low heating/cooling cost.

 

[Industrial Toys]

Stupid question maybe. But can't you get just the motor rewound?

Seems to me that buying newer stuff is usually just a trap to spend even more money in the future. A HVAC tech told me that the most sophisticated furnaces are by far the worst for getting rid of your money!
My Dad has a Lenox gas furnace from 1966, that has only ever needed a few blower motors, usually junk yard finds.

 

[davesl708]

Stupid question maybe. But can't you get just the motor rewound?

Seems to me that buying newer stuff is usually just a trap to spend even more money in the future. A HVAC tech told me that the most sophisticated furnaces are by far the worst for getting rid of your money!
My Dad has a Lenox gas furnace from 1966, that has only ever needed a few blower motors, usually junk yard finds.

You have a valid point. However gas furnaces from the 60's, 70's and 80's had about a 60 to 70% efficiency rating.
When I needed to replace my 30yr old furnace and AC the best life expectancy was 10yrs according to the contractors. At $12,500 for a high end gas/electric made the geothermal very attractive. My house is total electric with a large hot tub running year round. My summer bills never get over $66 and winter have not exceeded $134. That is over $100 per month less than what I paid with the old system.

 

[Redneck in training]

After researching it a little bit I decided to replace the compressor. New unit that is only marginally more efficient cost 12000 USD or 7500 USD after tax rebates. Since it doesn't have desuperheater it is actually less energy cost effective. I also have DIY PLC based control system that integrates heating with HW and provides, heat zoning and switching between heating and cooling modes. Since new unit control algorithm works somewhat differently I would have to modify my PLC and rewire it to some degree.
I got several quotes within about 100 USD apart. About 1850-1950 installed. Only one guy itemized it. $450 for refrigerant, 4 hours for labor @ 86/hour and 1050 for compressor. I also added soft start because I think it will prevent lights blinking and frying the contactor that is apparently somewhat undersized. It adds, I think, $400.

 

[KYKub]

Good luck with the unit. Sounds like you made a good, reasoned, decision. I hope you get a longer service life from the new compressor!

 

[truckdiagnostics]

When we replaced ours, got the soft start, worth it, makes a difference. lMO already being at r410a no reason to go new.

 

[Industrial Toys]

That technicain showed me the soft start DC motor that had to be replaced. It was well over a grand! The funny thing is, it was an AC motor with an extended end with some electronics. What a rip-off! The exhaust motor was similar!

 

[Redneck in training]

That technicain showed me the soft start DC motor that had to be replaced. It was well over a grand! The funny thing is, it was an AC motor with an extended end with some electronics. What a rip-off! The exhaust motor was similar!

The softstarter is external to the compressor. It is made by Hyper Engineering in England (Ithink) and sold under Intelistart by Waterfurnace.

 

[doxford jim]

Stupid question maybe. But can't you get just the motor rewound?

Seems to me that buying newer stuff is usually just a trap to spend even more money in the future. A HVAC tech told me that the most sophisticated furnaces are by far the worst for getting rid of your money!
My Dad has a Lenox gas furnace from 1966, that has only ever needed a few blower motors, usually junk yard finds.

For all the hype about geothermal systems, I would think twice about replacing one with a new system. I have a waterfurnace ground loop system and have had a few things go wrong with it - some I fixed and some the original installer fixed. The parts were expensive and proprietry (own design and make).

If a person has gas service (or propane) I think a new high efficiency gas furnace would work well. Updating insulation and draught mitigation would make a big difference too - depending where you live.

While our system works well, ambient temperaures of -35C or -40C the system is working very hard to keep the place war (you can just see the kWh clicking away on the meter). When around -25C we use about 110kwh forenty four hour heating per day.

One other consideration is power outages. it would be much easier to keep gas furnaces and pellet stoves running with a standby generator than a heat pump system.

Just a few thoughts and felt they needed to be shared. Everyone's cirumstances are different of course, so what might be good for one household may not be the same for another.

 

[LD1]

While our system works well, ambient temperaures of -35C or -40C the system is working very hard to keep the place war (you can just see the kWh clicking away on the meter). When around -25C we use about 110kwh forenty four hour heating per day.

I think a big problem is HVAC installers like to size based on cooling load. It isnt as hard to keep a home 20 degrees (F) cooler than ambient than it is to keep it 80 degrees warmer.

Doing a manual J load calculation, heating load is usually around double the BTUs than cooling load. (I am getting ready to do a geo when the weather breaks and did a manual J) my cooling load is ~26k BTU and heating load right at 48k BTU. This is based on outdoor temps of 0F for heating and 95F for cooling.

So if sized according to a HVAC guy, I would get a unit that runs almost all of the time when temps are 95+ trying to keep the house cool (which is what they want for humidification). But anytime the ambient temps drop much below 30F (which is alot), the system cannot keep up and needs a backup source like heat strips. Sure dont sound efficient to me. I'd rather have a larger unit that dont run as often but is able to keep my house warm in the winter.

I am likely going to be installing a 4-ton based on my 48k heat load.