Ultra 155

init4years

Is the piping diagram in the install manual for the Weil Mclain ultra an antiquated design for a condensing modulating boiler, and would a larger primary loop work better in most applications ?

Tim McElwain

What is recommended in the

I and O manual is usually the best to follow. Why are you asking is there a problem?

Jean-David Beyer

install manual for the Weil Mclain ultra an antiquated design

I do not think the design W-M supply for near-boiler piping is antiquated. It seems to be quite similar to what John Seigenthaler shows in his big book. In  any case, I have never had any problems with the piping other than a ball valve whose bonnet needed tightening after a few months of operation, and a noisy circulator that needed to be replaced under warranty.



It might matter which W-M Ultra series you have. I have an Ultra 3 80, and I have read the Ultra 2 manual, though I no longer have a copy. Their piping diagrams were pretty much the same, if I remember correctly. W-M now make newer models that they do not call Ultra 4, and they seem about the same for piping as the Ultra 3s.



My installing contractor did a couple of things right. One was that they used 1 1/4 inch piping in the boiler loop, where for my model W-M said it must be at least 1 inch. This got the flow speed through the microbubble resorber to be lower.



The other thing they did was that W-M said the closely spaced Ts should be no more than 12 inches apart, but they put them 5 inches apart.

init4years

Thanks

Thank you for the input  I was not confident in the generic answers I received from WM

tech support.  The customer is complaining,  but more about the installing contractor the the operation

icesailor

Photogenic Piping:

Post some pictures of the piping. Especially the closely spaced tees and their orientation.

My personal opinion and practice with a 1" primary loop with 1" closely spaced copper tees is through the runs with a 3" copper nipple between the tee's, on the run. Both horizontal or vertical. Not both, one horizontal and one vertical with a 90* or a Tee in between.

My practice. Maybe wrong.

icesailor

Primary piping:

> JM-BIf your boiler is smaller than a 155, it says that it must be 1" or larger. And the closely spaced tee's no farther apart that 12". You won an all counts.