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Near boiler piping

digger_2 Member Posts: 39
Hopefully I will install my new boiler this week. Submitted for critique is an iso of the near boiler piping. This is exactly the layout arrangement plan. This is as close to the manufacturer's layout as possible and convenient . They don't have a diagram with a HX so I improvised.

The boiler is a Lochinvar WB-050, It has built in outdoor reset and DHW priority


The inlet and outlet temperature sensors will be where you would expect them to be. The system temperature sensor will be on the HX outlet "to radient floor system".

Radient side of HX is already piped temporarily to the old heat plant. A 50 gal water heater.

All three pumps are Grundfos UPS15-58 3speed

May add  valves to isolate DHW from heating.

This is for personal use so servicability (quick pump changes, etc.) not that important. I am retired.


  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    That will work, but...

    If you chose a larger pump, you could use just one pump for space heat where you currently show 2. You'd have to size it for 5 GPM and the combined pressure drop of the boiler HXer and the FP HXer, but ti will work.


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  • EricAune
    EricAune Member Posts: 432
    edited January 2010
    Looks Good

    I must assume you are isolating the boiler from the radiant side for tubing/barrier reasons.  When using a plate exchanger I would consider using a stainer on the inlet of the system side.  This will lengthen the life of the exchanger and maintain efficiency.  Some maintenance needed.

    I do not know what is on the system side of the exchanger, but please remember to allow for expansion there too.  (You probably have thought of all this, just thought I'd bring it up)

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  • digger_2
    digger_2 Member Posts: 39
    revision 1

    Iso revised per ME's suggestion. I think I can still use the UPS15-58FC for SH loop. The HX is a 20 plate with very low head loss. It will be close. If I end up needing more pump, l can switch to the UPS26-99FC that was shipped with the boiler. It is more than needed on low speed.

    Also am adding power purge to SH loop. adding PT plugs before and after HX to monitor for fouling.

    Piping is all copper and brass construction. The cast iron pump housings are the only ferrous material in the system. Does that mean the will take most of the the hit corrosion wise?
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