Hot water recirculating pump setup - Page 2

stevehull · 11-13-16, 08:55 AM

Oilpan,

I am designing the complete energy package for them (geothermal heat pumps, radiant flooring, PV solar, etc) and the new home will have a total of 600 amp service. Current to a tankless electric unit is not a concern.

Steve

oil pan 4 · 11-13-16, 09:15 AM

Then 5kwh a day sounds like a good estimate even if preheat doesn't work as well as we would like to see.

jeff5may · 11-13-16, 12:36 PM

OK, so for the cheapest rig in the world, just buy a recirculator pump without a timer. Buy a clip-on snap-disc aquastat and clip it onto your return line. Wire the aquastat in series with the pump. Obtain power from the light switch in the room nearest the end of the hot water line. Tada, enjoy. Not quite as precise or adjustable as a valve-style aquastat, but it will do the job.

563-2 - Taco 563-2 - Temperature Aquastat for "00" Series Circulators (95°F - 115°F )

oil pan 4 · 11-13-16, 03:01 PM

I got some normally closed 45°C type KSD301 thermal switches. They are cheap $5 for 5 of them.

The cheapst listed hot water recirculating pump I can find is the watts pump at lowes.

jeff5may · 11-14-16, 06:37 AM

If cheap is the goal, go with what Mike said earlier. A brushless DC motor wired to a wall wart will start out around 20 bucks. A real, plumber approved, industry standard recirculator pump will begin above 100 bucks. Make sure if you get a cheapie that it can handle the temp and pressure.

oil pan 4 · 11-14-16, 09:26 AM

Yeah I'm going with the listed pump.
We have up to 100 psi of water pressure here and a leaking pump could cause thousands of dollars in damage so I don't mind spending the $ on an appropriate pump.

NiHaoMike · 11-15-16, 10:01 AM

Here's a high pressure Laing D5 going for just under $180.
https://smile.amazon.com/Solar-Pump-.../dp/B007ETI63I

mk1st · 12-19-16, 12:16 PM

Quote:

Originally Posted by oil pan 4

I always hear tankless heaters save water.

I always tell my customers who are considering one that it's not the unit that saves that much money or energy, it's how you use it. If a teenager can take an endless shower they will!

11-13-16, 08:55 AM	#11
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	Oilpan, I am designing the complete energy package for them (geothermal heat pumps, radiant flooring, PV solar, etc) and the new home will have a total of 600 amp service. Current to a tankless electric unit is not a concern. Steve __________________ consulting on geothermal heating/cooling & rational energy use since 1990

11-15-16, 10:01 AM	#17
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	Here's a high pressure Laing D5 going for just under $180. https://smile.amazon.com/Solar-Pump-.../dp/B007ETI63I __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...

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11-13-16, 09:15 AM	#12
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	Then 5kwh a day sounds like a good estimate even if preheat doesn't work as well as we would like to see.

11-13-16, 12:36 PM	#13
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 432 Thanked 619 Times in 517 Posts	OK, so for the cheapest rig in the world, just buy a recirculator pump without a timer. Buy a clip-on snap-disc aquastat and clip it onto your return line. Wire the aquastat in series with the pump. Obtain power from the light switch in the room nearest the end of the hot water line. Tada, enjoy. Not quite as precise or adjustable as a valve-style aquastat, but it will do the job. 563-2 - Taco 563-2 - Temperature Aquastat for "00" Series Circulators (95°F - 115°F )

11-13-16, 03:01 PM	#14
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	I got some normally closed 45°C type KSD301 thermal switches. They are cheap $5 for 5 of them. The cheapst listed hot water recirculating pump I can find is the watts pump at lowes.

11-14-16, 06:37 AM	#15
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 432 Thanked 619 Times in 517 Posts	If cheap is the goal, go with what Mike said earlier. A brushless DC motor wired to a wall wart will start out around 20 bucks. A real, plumber approved, industry standard recirculator pump will begin above 100 bucks. Make sure if you get a cheapie that it can handle the temp and pressure.

11-14-16, 09:26 AM	#16
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	Yeah I'm going with the listed pump. We have up to 100 psi of water pressure here and a leaking pump could cause thousands of dollars in damage so I don't mind spending the $ on an appropriate pump.