Heating Problem

[DBM481]

I have a problem with my heating system. The problem is the upstairs rads are hwating fine but the downstairs are cold. I recently fitted a new circulating pump and replaced a faulty zone valve. Can any of these be the problem, I completely drained the system and refilled it thinking there may be a air lock.
Can anybody help

Thanks.

DBM481

[johnjh2o]

You have air in the system. Just refilling it doesn't remove the air. You must open the air vents until you get water to remove the air. What type radiation do you have? Is it radiators or baseboard? Depending on the system if it's baseboard the vents should be at the ends of the baseboard.

John

[LiQuId]

I am thinking that air lock may not be your problem ( though it may indeed be ) being in that you say that your upstairs radiators are fine and your main floor are not. where did you replace the zone valve ? ( was it in the main floor zone being affected ) and did you repklace it with the same type ?? these can be normally open, closing when the thermostat is satisfied or normally closed, opening when there is a call for heat.

was the zone valve faulty ?? how did you determine this ?

And, were you sure to install the pump, pumping in the right direction ??

I dont mean to sound insulting in anyway asking these questions, just trying to get a better understanding as to what we're up against.

if it were the upper floors I would bet all my horses on Air lock.. main floor.. I'm thinking zone valve.

[DBM481]

When filling the system I had water coming out air vent on all rads.

[DBM481]

The heating is not on separate zones.Yes i did replace with same valve the other valve was leaking

[LiQuId]

these valves look very similar is why i ask, the Normally closed one will have a handle on the side the normally open one does not. Are you sure that your upstars and downstairs are not on seperate zones?? this would be a very odd situation if so.

do you have the old one around, perhaps compare the 2 and check that the rating plates match.

these are the things that it COULD be.

Faulty thermostat... bypass thermostat or test with multi meter.

faulty zone valve ...check valve operation

no power to zone valve.. check for 24 vac with multi meter

circulator not running or installed incorectlly... verify pumping direction and voltage, check for any piping restrictions.

a picture of the setup would help.. it is odd that the main floor is cold while the top is heating, could be just gravity convection hapening..

check around the baseboards, I would wager that the up and downstairs are on seperate zones..

[johnjh2o]

Why would you have two zone valves if you have only one zone? If the home is on one zone there would be no reason to have any zone valves. Unless the second zone is for a indirect water heater. A picture would help I think were missing something here.

John

[LiQuId]

How big is the house? its fairly common to run more than a single zone on larger houses ( i'm thinking 2 floors here ) to better manage the living spaces. I see Second floor Thermostats On Many places here, I would check the perimiter of upstaris and downstairs to see if there are seperate zones. Im hearing
from OP.
"the heating worked and then I changed, Zone valve, recirc pump" Is this right DBM481 ?

so "upstairs is heating fine, downstairs is cold"

Circulating pump is working and installed in correct direction. check,

Verify that there is no air in System by bleeding each rad ( during this I look for zone controlls also )

zone controll ( or controlls ) are operating properly. Check

A Valve.... Did the OP check for a shut valve on the ends of the heating loop on the main floor ??

it there a place where a pipe could be exposed to drafts or freezing ?

whats the boiler look like ? are there multiple loops or one main? are there check valves in the system? if it Is one loop, then how are the radiators Balanced ? are there balancing valves that could be blocked ( needle valves ) ?

pictures would help for sure.. how old is the house ? when you say rad's, are we talking copper fin or old cast iron.

[DBM481]

Yes the second valve is for a Indirect Cylinder