[rakster]

I have a 1 year old system that has a boiler and an indirect water tank that is heated by the boiler. There are 3 zones: Upstairs, downstairs, and the water tank. There are manual values to block off each zone. My question is sometimes some radiators will be warm(usually those closest to the boiler) even when my thermostats are off and boiler relay is off(it's not a thermostat issue) . This isn't much of an issue when it's cold outside but during the switch of the seasons where i would like to have the zones totally off but also the ability to turn them on remotely(thermostat apps) it creates a problem. i spoke to the plumber that installed my system and he said it's due to gravity, and the only way to stop this from happening is to manually shut off the valves. I'm curious if he is BSing and there is something wrong with the system as it is or it's installed incorrectly, or it's just the way it is with the system, and it's up to me to manually close the valves. Also it's an efficiency thing, can't be good for a radiator to be on when the thermostat is off.

[Grady White]

There should be flow control valves, sometimes called flow checks, in the system to prevent the problem you are having. If they are there, they are either manually open or leaking through.

[rakster]

These are the valves I have: a blue and a yellow. The blue one is the one the plumber told me to turn off when the system is off. Is this what you are talking about? Or are the flow check valves different & automatic? My issue is when I open the blue granite valve but do not turn on that zone via thermostat, some hot water gets through to the radiator nearest to the boiler.Pictures of valves:Boiler Valves - Imgur

[Grady White]

Those are manual ball valves used to shut off flow. Can you provide some wide angle pictures of the boiler & near boiler piping?

[rakster]

I uploaded some more pics here https://www.dropbox.com/sh/vlcizto7l...wQ1mFa?dl=0Can you tell if I have flow control valves? Hopefully these shots show what you need to see.

[massplumber2008]

You should not have to touch any valves. Flow control valves are either missing or not in the pictures you uploaded. Here, if the flow control valves were installed you would no longer get gravity flow into the heat pipes/radiators when the boiler system called for heating the hot water. ALL boiler systems with multiple circulators get these installed on the FEED (supply) pipes out to the system or have them installed internal to the circulators.

[Grady White]

I wonder if the circulators have, or were supposed to have, internal checks.

[rakster]

Hum, Should the circulators have a model# on them? I can take a closer look at them and get back to you. I had a town inspector sign off on the system, wonder if they are a requirement. I'm having the plumber come back and explain exactly what's going on. Anything else I should ask him?

[Grady White]

If the plumber did not install either flow control valves or circulators with internal check valves, he needs to do so.

[rakster]

I guess that my problem, how do I definitively tell that I do not have them? Seems like you guys don't see the valves in the pics, the issue is that they may be inside the circulators. If he tells me they are in the circulators, then they must be broken or something.

[Mike45plus]

rakster,
Usually, circulators equipped w/ internal flow - checks, will have the letters IFC stamped on the rating plate, or, on the end of the motor. A piece of debris can get lodged in the spring or seat of theses internal check devices, which will lead to thermal syphon and unwanted heat...

[massplumber2008]

Yeah, those look like grundfos circulators. They usually have internal check valves. It looks like you're getting a leak by. Have your plumber investigate.

If the circulators have internal check valves it should be an easy fix, but I still want to know why he has you shutting off that blue handled ball valve... Please let us know when you find out.

[rakster]

I think you are right about the circulators, they say on them that they have a check valve see pics: https://www.dropbox.com/sh/6x8j0fv7j...JrRy3T83a?dl=0

I will call my plumber today and schedule and appointment. Mostly likely he had me shut off the valves before because he either didn't have time or didn't want to bother fixing the problem as we were approaching summer and closing off the zone would work just as well.

[Grady White]

If the check valves are indeed in the circulators, it is most likely some debris hung up in the check valve, as Mike45plus said.
Are the circulators installed on the supply or return piping? If you don't know, one way to tell is to look at the end of the circulator opposite the motor. There should be an arrow in the casting. Is the arrow pointing toward or away from the boiler?

[rakster]

The arrow is pointing toward the boiler. Is this the correct setup?

[Grady White]

With the arrow pointing toward the boiler, it tells me those circulators are on the return side. Today most, if not all, boiler manufacturers want them on the supply. I've had far better success with internal check valve circulators on the supply rather than the return.

[rakster]

So the plumber installed valves that hook up to the thermostats on the supply lines as a solution. Link here:https://www.dropbox.com/s/axcm5r0hul...%20AM.jpg?dl=0

[Grady White]

That should do the trick.