Boiler pumping the wrong way

Snowmelt

I went to a job today, two zones, but the supply, which is usually on top of the boiler is being used as a return and the return as the supply, the pump was mounted inside the boiler jacket. I didn’t want to take the jacket off and investigate further, I was called just to change the zone valves.

HVACNUT

What boiler and model?
Pics?

lchmb

so it's the direction of the zone valves or something else indicated it was backwards?

Snowmelt

direction of zone valve, the placement of the purging ( ball valve and hose bib. when I turn the t-stat up and the heat went the same way the zone valves where facing. I am going to assume the pump was going in that direction also.

unclejohn

Old cast iron boiler? Never be a afraid to investigate. Where would Holmes be with that attitude.

Snowmelt

yes old cast iron boiler

HVACNUT

Some of the old boilers have the circ on the return inside the extended jacket. The Weil McLain pancake, York Shipley, American Standard Arcoleader, etc.

unclejohn

Maybe who ever installed the zone valve in the first place didn't take the cover off either.

Snowmelt

I would agree with you but when running the boiler it did heat in the direction of the zone valves

lchmb

if they have no complaints over how it heats and how much fuel..I'd leave it.. Can fix it when they go with a new system..

Snowmelt

That’s what I am going to do.

jumper

Originally one circulator was supposed to make hot water heating foolproof. So much simpler than steam. Nowadays hydronic schematics resemble spilled spaghetti.