Plumbing for plate exchanger

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Lineman

New Member
Mar 29, 2014
2
Marcellus mi
New to forum 1st post recently purchase heatmaster mf5000 thinking of doing in trench closed foam for pex lines how much foam is needed for aprox. 120' I realize lot of variables. Should I hire foam guy or do my self with kit from eBay 200 400 600 board kit .also adding plate exchanger at w/heater do I need mixing value or is water temp going in w/h same as boiler water what's best way to go .
 
What does the heatmaster dealer tell you?
 
Your info is very sketchy. Based on experience, important considerations are: amount of heat (btu's) you need or want to be able to move between the boiler and the place you are heating; desired supply temp and return temp; round trip feet of pipe run; pipe diameter; gpm's needed to flow; pump head at required flow rate; plate hx pressure drop (pump head) Sides A and B at required flow rates and approach temperature; sizing of plate hx (l x w x #plates x port size); sizing of circulators on both sides of the plate hx to move required flow rate at pump head sides A and B.

This is not overly complicated for an experienced person, but I have heard too many stories which show in practice that the sales person does not know what he/she is doing. Your boiler is spec'd at 250,000 btuh, that's a lot of heat and requires a lot of flow and/or large temperature drop to get into a reasonable range of pump head; and a lot of that has to do with pressure drop in the thermopex and in the plate hx. Generally at delta-T=20F, flow rates should not exceed about 16 gpm for 1.25" ID pipe, 8 gpm for 1" ID, and 4 gpm for 0.75" ID. This equates to about 160,000 btuh for 1.25" ID pipe, 80,000 btuh for 8 gpm for 1" ID, and 40,000 btuh for 0.75" ID. Pay attention to inside diameter (ID), not outside diameter.
 
Only tip I can give with the pex lines. I ran 1" and wish I had used 1 1/4. I think my owb was producing more btu's than i could transfer to my house. If I did it again I'd rather move more than I need then wish I had more.
 
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