My geothermal compressor just died.

[LD1]

Sounds like you guys have units oversized according to every pro I talk to that wants to size me a unit. If you aren't on backup heat by 25-30 degrees they think it's too big.

The thing about a manual j...it can be deceiving. You calculate it around a design temp. IE, what temp do you want to maintain and at what ambient outside temp.

So if whoever does the manual j calculates based on 68* inside and 25* outside...and you want to keep the house 72* and it frequently gets to teens or single digits, your system will be too small and need backup very frequently

 

[midwesternhayfarmer]

I am afraid they have me by the b**s. There are not that many choices between installers. I would switch brands if I know which to select. There are complaints on internet about all of them.

Clarke electric the original installer?

 

[buckeyefarmer]

I ran my own manual j, and designed my systems, and installed my systems. Used to be IGSHPA accredited but i let it expire. I prefer to minimize backup electric. My breaker is off on mine, has called for it for 5 hrs so far this month.

 

[TheGoose]

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.

How exactly do you do a manual j load calculation?

 

[buckeyefarmer]

Manual j is a book put out by ACCA that tells you. Most buy the software. I have both but software license is now expired.

 

[buckeyefarmer]

You can do manual j by hand, but is a pain. Calc for each room, each surface area the thermal conductivity to determine amount of heating,cooling, airflow required to maintain an indoor temp versus outdoor temps.

 

[Redneck in training]

Clarke electric the original installer?

It was not Clarke Electric. It was LessMess out of Truro. Clarke Electric is out of geothermal business.

 

[fordmantpw]

Sounds like you guys have units oversized according to every pro I talk to that wants to size me a unit. If you aren't on backup heat by 25-30 degrees they think it's too big.

If you are talking about the resistance heat as backup, for a ground-source unit, you only want that to come on as a worst-case because it is so expensive to run.

Our unit is sized to heat and cool our house without the backup heat to the coldest weather expected here in MO. We have a variable everything unit (compressor, pump, fan), and our heat strips are actually disabled and have to be turned on as 'emergency' heat. Now, when it gets cold, our unit runs a lot, A LOT! Our thermostat tells us how much it runs and we've had days where it has run for 22 hours in a day. Now, most of that is running on a low power setting, which is where the GSHP really shines. Basically, we are heating our entire 2500 sq. ft. main level plus finished basement with WAY too many windows for about what it takes to run a 1500 watt ceramic heater (based on the reading on our thermostat), even in the coldest weather. To me, that's pretty impressive. Our electric bill runs about $30/month more in the coldest months than when we have no heat or air on at all. Our bill doesn't change much when the A/C is on because it saves money not having to pay to heat our water.

 

[Redneck in training]

Variable everything is great and way to go. But it is hard to retrofit. It needs a control system that integrates all parts together.

 

[davesl708]

If you are talking about the resistance heat as backup, for a ground-source unit, you only want that to come on as a worst-case because it is so expensive to run.

Our unit is sized to heat and cool our house without the backup heat to the coldest weather expected here in MO. We have a variable everything unit (compressor, pump, fan), and our heat strips are actually disabled and have to be turned on as 'emergency' heat. Now, when it gets cold, our unit runs a lot, A LOT! Our thermostat tells us how much it runs and we've had days where it has run for 22 hours in a day. Now, most of that is running on a low power setting, which is where the GSHP really shines. Basically, we are heating our entire 2500 sq. ft. main level plus finished basement with WAY too many windows for about what it takes to run a 1500 watt ceramic heater (based on the reading on our thermostat), even in the coldest weather. To me, that's pretty impressive. Our electric bill runs about $30/month more in the coldest months than when we have no heat or air on at all. Our bill doesn't change much when the A/C is on because it saves money not having to pay to heat our water.

The frequency in which a unit runs is determined by the heat load on the structure, i.e. insulation and air exchange. The less air exchange and greater the insulation reduces the frequency the unit runs. The duration of the run is determined by the btu's produce by the unit. The greater the btu's the less time the unit runs.
My unit comes on about every hour and runs for 10 minutes. Less during the summer.

Definitely the benefit of the geo producing hot water is a big savings.

 

[Redneck in training]

Definitely the benefit of the geo producing hot water is a big savings.

Which reminds me to descale the desuperheater.

 

[LD1]

The frequency in which a unit runs is determined by the heat load on the structure, i.e. insulation and air exchange. The less air exchange and greater the insulation reduces the frequency the unit runs. The duration of the run is determined by the btu's produce by the unit. The greater the btu's the less time the unit runs.
My unit comes on about every hour and runs for 10 minutes. Less during the summer.

Definitely the benefit of the geo producing hot water is a big savings.

That is basically what a manual j figures.

You can have 10 different people do a manual j and have 10 different results. All will be close, but different. Just depends on how picky and exact you want to get.

Some variables are obviously build type, size, insulation, window size and type of glass. But some other factors are basement, any exterior insulation or under slab insulation, number of people living there, wall and window orientation to the sun, natural shading and overhangs, appliances, vents, etc.

It can get quite in depth. But it basically figures how many BTUs are required to keep your house a given amount warmer or cooler than the outside.

And the law of diminishing returns applies.as the temp difference increases, the BTUs grow exponentially. IE doing a manual j for outdoor temps of 40 then 30 that extra 10 degree difference is gonna require a given BTUs. Same figures but going from 10 to 0...THAT 10 degree change is gonna take MORE BTUs than going from 40-30

 

[midwesternhayfarmer]

It was not Clarke Electric. It was LessMess out of Truro. Clarke Electric is out of geothermal business.

Clarke installed mine originally. Looking for a good serviceman for checkups.

 

[truckdiagnostics]

Couple posts up some one mentioned that all Geo unit are about equal as all are getting complaints. Also, couple post up some one mentioned that there are just a few compressor manufacturers. With that in mind IMO the reason Geo thermal is getting so many complaints is the systems are not being designed correctly. For the most part generally speaking the units them selves are really close. Also IMO the use of a buffer tank, which red neck is using, allow the unit to run longer then shut off. It may not be variable displacement everything it is mimicking it. My concern with the variable everything is the complexity and there for maintenance costs. I keep going back to the unit running the shop(17 years old), runs a buffer tank, works its but off when it gets cold, never misses a beat. Cold winters I can freeze up the loop. That is not the units fault. I am just asking it to do more than it was designed for. This is what we use for buffer tank.
Marathon Water Heaters by Rheem
How we do are potable hot water is, geo brings water temp up to 90 then tank elements bring it up the rest of the way. Then water to water exchanger for in floor heat.

 

[truckdiagnostics]

Couple posts up some one mentioned that all Geo unit are about equal as all are getting complaints. Also, couple post up some one mentioned that there are just a few compressor manufacturers. With that in mind IMO the reason Geo thermal is getting so many complaints is the systems are not being designed correctly. For the most part generally speaking the units them selves are really close. Also IMO the use of a buffer tank, which red neck is using, allow the unit to run longer then shut off. It may not be variable displacement everything it is mimicking it. My concern with the variable everything is the complexity and there for maintenance costs. I keep going back to the unit running the shop(17 years old), runs a buffer tank, works its but off when it gets cold, never misses a beat. Cold winters I can freeze up the loop. That is not the units fault. I am just asking it to do more than it was designed for. This is what we use for buffer tank.
Marathon Water Heaters by Rheem
How we do are potable hot water is, geo brings water temp up to 90 then tank elements bring it up the rest of the way. Then water to water exchanger for in floor heat.

 

[fordmantpw]

The frequency in which a unit runs is determined by the heat load on the structure, i.e. insulation and air exchange. The less air exchange and greater the insulation reduces the frequency the unit runs. The duration of the run is determined by the btu's produce by the unit. The greater the btu's the less time the unit runs.
My unit comes on about every hour and runs for 10 minutes. Less during the summer.

Definitely the benefit of the geo producing hot water is a big savings.

You are correct. And if yours runs for 10 minutes every hour then either 1) it's not losing much heat to outside or 2) it's using more BTU than it needs to in order to keep the house warm. The geo at our last house was like that.

That's what I love about our variable system. It runs at such a low power that when it is really cold out, it is essentially running just to replace the lost heat in real-time, at such a low power. Another note is that we have 5 different zones in our house, so it is constantly switching between zones.

IMO the reason Geo thermal is getting so many complaints is the systems are not being designed correctly. For the most part generally speaking the units them selves are really close.

Agreed! You need a geo specialist to really get it right. Sizing for geo is different than sizing for gas if you want the best possible efficiency out of your unit.

 

[Redneck in training]

Clarke installed mine originally. Looking for a good serviceman for checkups.

There is little to check up IMO. It is wasted 200 or whatever they charge. The HP itself is all sealed. If you have forced air then you can check the fan (bearings) and clean the heat exchanger, change the filter. That is easy to DIY.

 

[davesl708]

You are correct. And if yours runs for 10 minutes every hour then either 1) it's not losing much heat to outside or 2) it's using more BTU than it needs to in order to keep the house warm. The geo at our last house was like that.

That's what I love about our variable system. It runs at such a low power that when it is really cold out, it is essentially running just to replace the lost heat in real-time, at such a low power. Another note is that we have 5 different zones in our house, so it is constantly switching between zones.



Agreed! You need a geo specialist to really get it right. Sizing for geo is different than sizing for gas if you want the best possible efficiency out of your unit.

My house is much more energy efficient since the system was installed. I found that several of the geo installers were selling geo on the side to cover all bases. They were gas/electric vendors primarily. I found through recommendations a Waterfurnace dealer that did only geo and had been in business for 40 years. I smile every time the electric bill arrives and my neighbors complain about their $200 to $300 bills.

Plus when we sit outside in the summer no noisy outside condenser running.

 

[Redneck in training]

I was hoping the HVAC people would fix my HP today because of low temperatures and high wind predicted for Sunday. They promised to do it Monday now. Fortunately we installed two propane fireplaces when we built the house so the situation is not critical.

 

[buckeyefarmer]

My upstairs has run 80% of the time this month, 17% on high. Down ran 55%, 3% on high. We've had at least 3 nights out of 15 at 10° lows.