EcoRenovator - View Single Post - Hydronic Floor pump frequency vs water supply temp?

Mikesolar · 11-15-12, 08:23 AM

I have to disagree here. The MAX floor surface temp should be about 85F. By using a high input temp you are using a big V8 engine, gunning it, then putting on the brakes till it comes down then repeating. This is not the way to heat. If you are using a gas boiler or tank, the lower your temp the higher your efficiency, as much as 20% better. Plus every start and stop of a pump or boiler is done at a very low efficiency. The electrical cost for a small circulator is about $20/year. There is no point in not running it flat out.

Higher input temps also mean higher heat loss near the tubing and we don't want this. So, the rule of thumb is as tight a tube spacing as possible, and as low a water temp as possible. If you every want to use a HP or solar for heating, you will be able to use much more of your heating source with a lower temp.

Also 145 is way too high for DHW, most showers run at 105F or less when measured and 145F is a waste of energy. Anti-scald valves are set for 120F max so why heat higher?

11-15-12, 08:23 AM	#7
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	I have to disagree here. The MAX floor surface temp should be about 85F. By using a high input temp you are using a big V8 engine, gunning it, then putting on the brakes till it comes down then repeating. This is not the way to heat. If you are using a gas boiler or tank, the lower your temp the higher your efficiency, as much as 20% better. Plus every start and stop of a pump or boiler is done at a very low efficiency. The electrical cost for a small circulator is about $20/year. There is no point in not running it flat out. Higher input temps also mean higher heat loss near the tubing and we don't want this. So, the rule of thumb is as tight a tube spacing as possible, and as low a water temp as possible. If you every want to use a HP or solar for heating, you will be able to use much more of your heating source with a lower temp. Also 145 is way too high for DHW, most showers run at 105F or less when measured and 145F is a waste of energy. Anti-scald valves are set for 120F max so why heat higher?