primary/secondary tee spacing

bobby_3

We installed a weil-mclain ultra 155 with a plus 40 indrect water heater and they put the secondary tees about 18" apart and the tees for the indrect are in between the tees for the secondary loop. what problems will this cause?

Terry Trommeshauser

Not quite clear. a pic or drawing would help.

Secondary close-knit tees shall be MAX 4x pipe diameter spacing.

I would have put the indirect in with supply & return pipied directly to boiler supply/return with separate circ for indirect heater and put the DOM on Priority.

hope this helps.

Paul Rohrs_4

Bobby

If this is the way they have it piped, you would just be short-cycling the DHW loop (if the boiler pump dropped out)
and the boiler would not get any flow thru the HX. See "Bobby G" JPEG.

I would tap the tee's for the indirect and make them my boiler loop, then run the indirect as priority with flow-checks. See "Corrected" JPEG.


Regards,

PR

Buzz G.

P_S loop

If the IDHW and the boiler circs are about the same it should not make any difference as the flow will all go to the IDHW when it is calling and all go to the system when it is calling with the individual zones taking what they will from the system. I have Knight boiler and the sec tees are about 12-14 inches apart and when the system calls you can feel the piping and see that the entire circ goes to the system and the connection between the tees barely has any circulation in it. The 18" is theoretically too long, but you really aren't talking P-Sec here much. Do you agree Paul?