Adding 3 way bypass valve

Reply

  #1  
Old 09-16-08, 03:32 PM
Member
Thread Starter
Join Date: Sep 2008
Location: Upper Peninsula of Mi.
Posts: 12
Received 0 Votes on 0 Posts
Question Adding 3 way bypass valve

I have a Lennox downflo oil furnace with a honeywell 5 wire CT 31 thermostat. I have just installed a water to air heat exchanger under the furnace. I want to install a Taco 560 3 way bypass valve so my water will keep circulating and heat my DHW.Do i need to hook the bypass valve to a seperate thermostat? How do I keep the blower working for the heat exchanger and not have the oil kick in?
Thanks, Greg
 
Sponsored Links
  #2  
Old 09-17-08, 03:56 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
I just saw your post, I am going to have to a little research on this and get back to you..

is this water coil getting hot water from a wood boiler?
 
  #3  
Old 09-17-08, 04:37 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
ok, What made you go with this valve?

Is the pump running all the time? (or what controling that?)

Is there A/C on this furnace?
 
  #4  
Old 09-17-08, 04:52 PM
Member
Thread Starter
Join Date: Sep 2008
Location: Upper Peninsula of Mi.
Posts: 12
Received 0 Votes on 0 Posts
Thanks for the reply! The heat is from outdoor wood boiler,the pump will run all the time and if it would help I can get a different valve. No a/c.
 
  #5  
Old 09-17-08, 05:12 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
Ok, we may need to look into another valve.

The one you picked has a 120 volt side for control like a pump or burner.

i am heading out for dinner, and will eb back later.
 
  #6  
Old 09-18-08, 05:35 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,928
Received 0 Votes on 0 Posts
Wood Fired Boiler

Do you intend to keep the oil burner in service as a backup? If so, you would probably be wise to get a two stage thermostat.
 
  #7  
Old 09-18-08, 06:37 PM
Member
Thread Starter
Join Date: Sep 2008
Location: Upper Peninsula of Mi.
Posts: 12
Received 0 Votes on 0 Posts
Ok I will look for a two stage thermostat. Do you know what brand of 3 way zone valves does not have a 120 volt side?
 
  #8  
Old 09-18-08, 07:50 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
Any 3 way valve that is only 24 volts will work.

Grady may have more info on his hand since he around hot water heat more than I am.

That is what I was planing on doing is use the 2 stage t-stat like Honeywell RTH7400 model.
 
  #9  
Old 09-19-08, 05:13 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,928
Received 0 Votes on 0 Posts
Originally Posted by woodworker2 View Post
I have a Lennox downflo oil furnace with a honeywell 5 wire CT 31 thermostat. I have just installed a water to air heat exchanger under the furnace. I want to install a Taco 560 3 way bypass valve so my water will keep circulating and heat my DHW.Do i need to hook the bypass valve to a seperate thermostat? How do I keep the blower working for the heat exchanger and not have the oil kick in?
Thanks, Greg
Greg,
Several questions popped into my head after re-reading the original post.
1. Do you realize the 560 is only a 1/2" valve?
2.I don't understand the part about heating the domestic. Are you heating the DHW via an indirect & is it not on a dedicated zone?
 
  #10  
Old 09-19-08, 07:03 PM
Member
Thread Starter
Join Date: Sep 2008
Location: Upper Peninsula of Mi.
Posts: 12
Received 0 Votes on 0 Posts
The DHW is in the main line before the heat exchanger. I found a valve to use it is a siemens/powers MXE series 24 volt 3 way diverting valve without a 120 side. I am going to get a RTH7400 thermostat probaly tomaro then i just need to know how to wire the thermostat up.
 
  #11  
Old 09-19-08, 07:23 PM
Member
Thread Starter
Join Date: Sep 2008
Location: Upper Peninsula of Mi.
Posts: 12
Received 0 Votes on 0 Posts
Someone in another forum says i need to use a seperate 24 volt transformer for the zone valve or you i will burn mine out is this true?
 
  #12  
Old 09-19-08, 07:27 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
Guess it depends on how big the zone valve will be.

Look at your current transformer and see what the VA rating is... it it turns out to be to low, then just need to upgrade the transformer to a stronger one.
 
  #13  
Old 09-19-08, 07:38 PM
Member
Thread Starter
Join Date: Sep 2008
Location: Upper Peninsula of Mi.
Posts: 12
Received 0 Votes on 0 Posts
My transformer is a 40VA what else do i need to know if that is enough
 

Last edited by woodworker2; 09-19-08 at 07:54 PM.
  #14  
Old 09-20-08, 10:52 AM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,928
Received 0 Votes on 0 Posts
Taco Zone Valve

Originally Posted by woodworker2 View Post
The DHW is in the main line before the heat exchanger. I found a valve to use it is a siemens/powers MXE series 24 volt 3 way diverting valve without a 120 side. I am going to get a RTH7400 thermostat probaly tomaro then i just need to know how to wire the thermostat up.
I didn't see where the Taco valve has any 120 volts connected to it & should you ever need to replace the power head, I'm sure the one for the Taco would be much easier to find.
http://www.taco-hvac.com/uploads/FileLibrary/100-3.pdf

Maybe I'm a bit dense on how the DHW is connected but having the domestic & a space heating coming off the same loop sounds really strange & could lead to gross overheating of the domestic. If you could take some pics of the system, post them on photobucket.com or similar photo sharing site, & provide us a link to the pics, it might help this old dummy understand.
 
  #15  
Old 09-20-08, 10:56 AM
Member
Join Date: Sep 2008
Location: 18255 pa
Posts: 2
Received 0 Votes on 0 Posts
Transformer size

40 va may be enough, but it may fail if your house voltage goes low. I like to use a 75 va with built in fuse or breaker. That way if it trips you have a chance of trouble shooting the circuit without buying an expensive tranformer replacement. A taco valve usually pulls 1.2 amps on it, close to the 40 va limit. Also if more controls are on this circuit it might go.
 
  #16  
Old 09-20-08, 01:08 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Received 0 Votes on 0 Posts
Originally Posted by Grady View Post

Maybe I'm a bit dense on how the DHW is connected but having the domestic & a space heating coming off the same loop sounds really strange & could lead to gross overheating of the domestic.
You are not the only one Grady, I am thinking the same thing as you are too.. "The house hot water is going to way too hot"
 
  #17  
Old 09-20-08, 01:27 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,928
Received 0 Votes on 0 Posts
Domestic

The only way I can envision where a setup like this would be safe would be to have the domestic heated via an external heat exchanger. In an external exchanger application the boiler water is pumped thru one side & the domestic thru the other & back to a storage tank. The domestic pump would be controled by an aquastat on the tank.
 
  #18  
Old 09-21-08, 09:37 AM
Member
Thread Starter
Join Date: Sep 2008
Location: Upper Peninsula of Mi.
Posts: 12
Received 0 Votes on 0 Posts
The DHW is heated via a side arm water heater. I got the RTH7400 thermostat. Now I have to get the valve and maybe a 75VA transformer to be safe.
 
  #19  
Old 09-21-08, 10:16 AM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,928
Received 0 Votes on 0 Posts
Transformer

No need for a 75 VA transformer. A 40 will handle up to 3 zone valves.

The side arm water heater has a separate bronze or stainless circulator for the domestic side & circulates from & to a storage tank?
 
Reply

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: