GV90+ the piping.

Tom_133

So if you look in the piping schematics from WM, there is no arrangement that allows the hot water heater to be fed from the primary loop except in the multi boiler arrangement and it shows as you see in the screen shot.

So I called and explained i am only using one boiler, and replacing an WM Ultra. The arrangement of piping is a tee on both the supply and return before the closely spaced tees.

I asked if I could do a set of closely spaced tees on the supply before closely spaced tees for the secondary loop, and was told NOTHING is allowed in the primary loop! I asked why they felt that a 3 way valve is better than two closely spaced tees as we see in the pic above and he was not hearing it. If you used a 3 way the customer would be left to ensure the right amount of flow could make it through the HX and that the internal pump to the boiler could handle it!!

Anyone see a conflict with just popping a set of closely spaced tees in after the supply and before the closely spaced tees? Im not asking for permission, I understand that if I do a piping arrangement unlike what was allowed by WM I will be left to own it!! But, what I am asking is based on what is drawn, and knowledge of the internal piping of that boiler, you think it'll work?

Jamie Hall

On your diagram, what control is there as to how much flow goes through the indirect vs. going through the rest of the system? (I'm presuming the indirect is the box on the right in the drawing)

Tom_133

Sorry for the confusion Jamie. The box on the right is the GV90 and the indirect is on the left.

I went to the job yesterday and it wont be that tough to just put the indirect on the secondary loop. But I am still curious, is the layout I show ok?

hot_rod

it is piped as a parallel loop in that pic, just using a 3 way zone valve to enable from a DHW call.

So it is using the onboard circs as the indirect pump, I assume

Here are two options they show with zone valves or zone pumps. I think the indirect could be one of the zones?

If you are zoning with valves a deltaP circ would eliminate the PAV #10