Posted By Princeton N.J. on 05 Feb 2011 08:58 PM
We only have one pump: A Bell & Gossett Series 1535 Close Coupled Centrifugal Pump. Does that sound right? Thanks.

So you use the same pumping power, no matter if one or both heatpumps are running? What size does the pump have? It goes from 351-3511.

This situation highlights a major frustration with internet support - this system SO NEEDS an inspection by someone who knows both sizing and geo.

Princeton has a fairly mild climate; 4 tons should suffice for all but the loosest oldest glassiest house in that area.

Operating cost of prior heating system and current cost per kwhr would help us put your bills in perspective.

WF has been more responsive lately to egregious screwups - stay on them and let them know you are here. It isn't the manufacturers fault that you got what sounds like an improper system, but it behooves them to facilitate an equitable solution to avoid being dragged through the mud.

Post your actual KwH consumption and your old system fuel consumption. At first glance it looks like your back-up heat is likely turning on a lot.

In the cold months, the KwH consumption is between 3000 and 6000. Very high for a house that tries to use little electricity. Is there any way that I can know if the back-up heat is coming on? Does it show up on the thermostat, maybe as Stage 3 or something?

I think it's 5 HP. Does that make sense?

Unfortunately I don't know much about the prior HVAC system. We bought a house that had a leaking underground oil tank and after the remediation was done, we moved in and installed our geo. Currently, we can use up to 600 KwH, in the coldest weather, even though our heat isn't set high (64-67 degrees).

Could you suggest a person or a department to call at WaterFurnace? I have found the company very hard to navigate as a consumer.

Thank you for your help.

Ooops, sorry -- I meant to say that our KwH can go up as high as 6000 in the coldest months. I would be very grateful for a  name of someone or a helpful department at WaterFurnace to contact if you know of one. I don't believe it's WaterFurnace's total responsibility to take care of my situation. But I do think that if a company decides to bring in business by designating certain contractors as preferred -- which was the case with my contractor -- the company has to understand that making someone an "official WaterFurnace installer" should mean something. I'd like to see some integrity behind the marketing.

I think it's 5 HP. Does that make sense?

Either it is 5 HP or it isn't. Where did you get that number and the pump specs? Off the motor plate? The pump plate? The proposal? The invoice?

Posted By Princeton N.J. on 06 Feb 2011 12:54 PM
I think it's 5 HP. Does that make sense?

If it is 5 HP you are getting killing by pumping costs, and that would explain your trouble. Better go back and double check. Model #?

Surely that is just a 0.5 (1/2) HP pump motor and not a full 5 HP. That would make it a Bell & Gossett #352 pump. The #352 pump can move up to 45 GPM at 40 ft head.

The 5 HP pump is only available with a 3 phase motor and is coupled to a #3511 pump capable of moving 240 GPM. Way overkill for this geothermal heat pump application.

Even 45 gpm at 40 ft of head would be way overkill, especially if the whole pumping power is running even if only one 4 ton is on. Each one of your HPs need about 12 gpm, pressure drop should be quite low, giving the 1.25" pipe in the borehole, and 3 well configuration. This could be the culprit. We need the model # of the pump.

Posted By docjenser on 07 Feb 2011 01:00 AM
Even 45 gpm at 40 ft of head would be way overkill, especially if the whole pumping power is running even if only one 4 ton is on. Each one of your HPs need about 12 gpm, pressure drop should be quite low, giving the 1.25" pipe in the borehole, and 3 well configuration. This could be the culprit. We need the model # of the pump.

Agreed.  I was thinking that even the 1/2 HP pump is ~twice the capacity that was needed (and double the electrical load).

Posted By Princeton N.J. on 05 Feb 2011 08:22 PM
Yes, there was a manual J load calc done

Did this calc yeild a number that you could share with us?
j

Here are the numbers from the Wrightsoft Load Multizone Summary Report:

Area ft2: 3078
Htg load Btuh: 75917
Clg load Btuh: 53179
Htg AVF cfm: 1830
Clg AVF cfm: 1830

appreciate your thoughts on this.

My mistake -- sorry, I'm really no expert on this stuff. It's a WaterFurnace 3/4 HP centrifugal pump CC6075T (1,3) BB.

Posted By Princeton N.J. on 07 Feb 2011 08:21 AM
Here are the numbers from the Wrightsoft Load Multizone Summary Report:

Area ft2: 3078
Htg load Btuh: 75917
Clg load Btuh: 53179
Htg AVF cfm: 1830
Clg AVF cfm: 1830

appreciate your thoughts on this.

And this was served by 8 tons?
Yeah I think the designers credentials are suspect.
j

Is 8 tons possibly too much -- or too little?

In fact, as I'm reminded that you have 2200 square feet, the load is suspect. I presume you don't live in Fairbanks......?
j

No we're in New Jersey! But I believe the discrepancy is that the designer counted inside closets, some of which are large (this place was built in the 70s -- houses and energy were cheap), and may have allowed for more sf because the house sits up off the ground on piers, for weird drainage reasons. So if the house is in total closer to 3000 sf and has an underside exposed --- would 8 tons still be way too much?

The load is 76MBH.
That is just over 6 tons.
How many jobs has your installer done?
j