EcoRenovator  

Go Back   EcoRenovator > Improvements > Geothermal & Heat Pumps
Advanced Search
 


Blog Register 60+ Home Energy Saving Tips Recent Posts Search Today's Posts Mark Forums Read


Reply
 
Thread Tools Display Modes
Old 12-21-17, 11:57 AM   #1
DonT
Lurking Renovator
 
Join Date: Feb 2016
Location: Northwood, Iowa
Posts: 27
Thanks: 2
Thanked 5 Times in 5 Posts
Default looking for mixing valve

I currently have an underfloor heating system with a 10 gal hot water heater that Im hope to convert to a GSHP system next summer. My current system is missing a mixing valve. At the timer the HVAC guy said I didnt need one, the system has been working fairly well. I have the water set at 175.
What I would like to do, is to use an Arduino to control a mixing valve. What Im looking for is a motorized 4-way mixing valve. Hot water in from boiler and return to boiler. Mixed water supply to and return from floor. thank you

DonT is offline   Reply With Quote
Old 12-21-17, 03:40 PM   #2
oil pan 4
Land owner
 
Join Date: Nov 2012
Location: NM
Posts: 1,010
Thanks: 12
Thanked 126 Times in 106 Posts
Default

What's wrong with a mechanical thermostatic mixing value?
oil pan 4 is offline   Reply With Quote
Old 12-21-17, 05:46 PM   #3
DonT
Lurking Renovator
 
Join Date: Feb 2016
Location: Northwood, Iowa
Posts: 27
Thanks: 2
Thanked 5 Times in 5 Posts
Default

what changes the set point when the outside temp drops?
DonT is offline   Reply With Quote
Old 12-22-17, 07:39 AM   #4
jeff5may
Supreme EcoRenovator
 
Join Date: Jan 2010
Location: elizabethtown, ky, USA
Posts: 2,394
Thanks: 410
Thanked 604 Times in 506 Posts
Send a message via Yahoo to jeff5may
Default

I see some holes in the story here, and details matter. Before anyone can recommend a system upgrade, the existing one needs described.
jeff5may is offline   Reply With Quote
Old 12-22-17, 09:14 AM   #5
DonT
Lurking Renovator
 
Join Date: Feb 2016
Location: Northwood, Iowa
Posts: 27
Thanks: 2
Thanked 5 Times in 5 Posts
Default

the system is: 10gal hot water heater set at 175 to an expansion tank to a temp/psi gage to the 4 zone manifold supply to the underfloor hanging 3 inches down back to the 4 zone manifold to the pump to a air trap back to the heater. what holes in my story do you see?
DonT is offline   Reply With Quote
Old 12-22-17, 11:50 AM   #6
geoff
Lurking Renovator
 
Join Date: Dec 2017
Location: Northern BC
Posts: 12
Thanks: 1
Thanked 0 Times in 0 Posts
Default

Lots on eBay! So many different flavors. You'll have to dig through the spec sheets.

Generally you purchase the valve body and actuator separate from each other. If you're trying to do this on a budget, it can take a lot of digging to find a cost effective pair.

The valve body choices are pretty obvious. The actuators are available in different voltages and modulating techniques.

Most on eBay are on/off control, no modulation.

Personally I like the floating actuators. Easy to control. Two pins: pulse one to close, one to close, and it'll hold its part-way position when power is removed.
geoff is offline   Reply With Quote
Old 12-22-17, 01:50 PM   #7
oil pan 4
Land owner
 
Join Date: Nov 2012
Location: NM
Posts: 1,010
Thanks: 12
Thanked 126 Times in 106 Posts
Default

You can get remote sensing mechanical thermostatic mixing valves.
I work in industrial automation and instrumentation.
oil pan 4 is offline   Reply With Quote
Old 12-23-17, 09:49 AM   #8
berniebenz
Helper EcoRenovator
 
Join Date: Apr 2012
Location: Gardnerville, NV
Posts: 64
Thanks: 0
Thanked 2 Times in 2 Posts
Default Maybe the HVAC guy is correct, you don't need a mixing valve.

Just control the water heater temp our of the heater and run the water directly to the distribution manifold.
berniebenz is offline   Reply With Quote
Old 12-23-17, 11:26 AM   #9
jeff5may
Supreme EcoRenovator
 
Join Date: Jan 2010
Location: elizabethtown, ky, USA
Posts: 2,394
Thanks: 410
Thanked 604 Times in 506 Posts
Send a message via Yahoo to jeff5may
Default

Ok, so you have a staple up or free hanging setup. That's not going to work real well with the lower water temperature that a heat pump provides. With the high water temperature you're using now, natural convection and radiation do a lot. These 2 effects go away drastically when you lower the loop water temperature.

With a solid slab, running a low temperature heating loop makes sense because of all of the thermal mass. With a thin floor, the heater pipes have to maintain direct contact with the surface they're going to heat. With most underfloor setups, this means heat spreaders. There's not much thermal mass, either. Lots of details to consider before you commit to a big system change.
jeff5may is offline   Reply With Quote
Old 12-23-17, 12:55 PM   #10
DonT
Lurking Renovator
 
Join Date: Feb 2016
Location: Northwood, Iowa
Posts: 27
Thanks: 2
Thanked 5 Times in 5 Posts
Default

Quote:
Just control the water heater temp our of the heater and run the water directly to the distribution manifold.
that's what I do now but when the temp drop's from 25 during the day to 5 at night the water temp I have set does not keep up. that's way I'm looking at a mixing valve

DonT is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:26 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Ad Management by RedTyger
Inactive Reminders By Icora Web Design