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All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: hrc200x on August 08, 2014, 08:07:15 AM

Title: water to water heat exchanger install question.
Post by: hrc200x on August 08, 2014, 08:07:15 AM
I'm prepping for my install by doing some figuring and homework early so can order fittings and pipe, etc. I have an existing fuel oil boiler which is going to stay, got a 5x12 80 plate exchanger to hook into it. My original though was to make a short loop through the plate exchanger and through the pop off valve and drain valve on the oil boiler with a pump that would keep the fuel oil boiler up to temp. This pump and the pump at the OWB would run 24/7. The zone circulator pump will only kick on when a zone calls for heat, complete system would have 3 pumps.

Now I'm thinking of running my fuel oil boiler return line through the heat exchanger before it gets to the fuel oil boiler. This way would reduce the amount of pipe needed, very nice since the area is already cramped, simplify install, one less pump in the system. Will the plate exchanger transfer enough heat from the OWB side to the indoor side when the zone pump comes on? One thing I'm thinking of is I may need a different aquastat relay on the indoor boiler with a little lower cut in value which would keep the fuel oil from coming on until water temp is lower than normal, 140-150?

Is there a way to tell how much heat will transfer in the water exchanger? If the water temp from OWB is coming in at 180, what temp is going out on the indoor boiler side?
Title: Re: water to water heat exchanger install question.
Post by: slimjim on August 08, 2014, 10:43:29 AM
It sounds like you need some impartial guidance, you have lots of options in your install and there are lots of ways to do it, If you would like we could have an offline phone conversation as I'm having a hard time wrapping my head around your questions, if you PM me your contact info I'll give you a call.
Title: Re: water to water heat exchanger install question.
Post by: LittleJohn on August 08, 2014, 10:58:20 AM
Well considering most 40-50 plates are good to about 500k btu/hr; I don't think you will have an issue with heat transfer in an 80 plate. 

Typically you want a drop of 10-20 degrees from supply to return of boiler; much more than that and you could potentially out run boiler or potentially cause condensation issues. 
Title: Re: water to water heat exchanger install question.
Post by: hrc200x on August 18, 2014, 03:35:09 PM
Is it possible to clean up and use old copper fittings and pipe. I've got some 3/4" pipes that were cut out of the house when I was fixing it up and now when I re-route some base board heat I may need some copper and fittings. I was able to pull apart one section of pipe no problem, that section I could see the silver of the solder in the joints. Another section of pipe I try seems no matter how much i heat it, it doesn't want to come apart and these joints appear dark colored, almost black. Guessing these pipes are from the mid 90s, they are laying loose in the garage, so no water is in them. Was there a different kind of solder available that requires alot of heat, or doesn't come apart at all?

If I can reuse the old fittings does all the silver color need to be removed from the copper pipe?

What kind of solder should be used?
Title: Re: water to water heat exchanger install question.
Post by: mlappin on August 18, 2014, 08:04:27 PM
Silver solder or A/C rated solder is tougher than regular ole plumbing solder.

The stuff the local welding shop uses to patch the odd hydraulic line is solder but they get the material almost hot enough to braze.
Title: Re: water to water heat exchanger install question.
Post by: hrc200x on August 18, 2014, 08:32:31 PM
As far as solder I see 40/60 and 95/5 and there is probably a few more, which one do I need?
Title: Re: water to water heat exchanger install question.
Post by: slimjim on August 19, 2014, 05:34:38 AM
 I use a product called Silva Brite, I think it is 95-5, I could check if you wish
Title: Re: water to water heat exchanger install question.
Post by: american-pacemaker on August 19, 2014, 09:52:24 AM
Hey slimjim the silvabrite 100 is supposed to be one of the best solder's but what flux do you use with it ?
Title: Re: water to water heat exchanger install question.
Post by: slimjim on August 19, 2014, 09:57:37 AM
I never paid attention but just checked, it says self cleaning solder flux, no name, straight off the shelf at Bell Simons.
Title: Re: water to water heat exchanger install question.
Post by: hrc200x on August 19, 2014, 04:28:26 PM
Are you around tonight slim? I will try you again. When do you usually go to bed? 
Title: Re: water to water heat exchanger install question.
Post by: slimjim on August 19, 2014, 05:08:47 PM
I'm usually told by the boss( my Wife ) to cease answering the phone and put away the I pad by around 8PM EST
Title: Re: water to water heat exchanger install question.
Post by: hrc200x on August 25, 2014, 08:43:25 PM
With a 5"x12"x80 plate exchanger is there a way to tell how much heat will get transferred from the OWB to the indoor oil boiler. For instance, 180 degree water coming into the exchanger on the OWB side what will the water temp be coming out of the exchanger on the indoor boiler side? Has anyone on here with a similar set up used a infrared temp gun and checked?
Title: Re: water to water heat exchanger install question.
Post by: slimjim on August 26, 2014, 04:15:27 AM
I use actual temp gauges on my manifolds, this way I can check differential across the heat exchanger at different times of the year and adjust the circs speed to control that differential
Title: Re: water to water heat exchanger install question.
Post by: hrc200x on August 26, 2014, 08:07:29 PM
I'm considering putting temp gauges on the supply and return lines at the boiler. What brand do you use, or better yet can you suggest one from this site as I have about $800 worth of stuff to order from there anyway. http://www.supplyhouse.com/Temperature-Pressure-Gauges-864000 (http://www.supplyhouse.com/Temperature-Pressure-Gauges-864000)
Title: Re: water to water heat exchanger install question.
Post by: Steinacher Sales on August 26, 2014, 09:10:27 PM
hrc200x,

Try altheatsuppy.com down load their catalog.

Hope this helps

Greg Steinacher
618-401-0726
www.midwestoutdoorfurnace.com (http://www.midwestoutdoorfurnace.com)
Title: Re: water to water heat exchanger install question.
Post by: slimjim on August 26, 2014, 10:27:36 PM
I use Pasco brand that I buy at the local supply house for about $15