Y plan system problem

[voovon]

I've just moved house, been in less than a month, since moving a radiator i've been having severe problems with my system.
After refilling and removing air, I found only the upstairs rads get hot, then suddenly the boiler wouldn't fire at all when CH was programmed to be on (hot water worked fine).

I found that the room stat had stopped clicking when turned so decided to replace, now boiler fires up fine when programmed for central heating as long as stat is turned high enough,
but also fires up when not programmed to be on at all! room stat will overide anything.
I can't say for sure if this is how it was before, when the old stat was working.

My system is ;
Glowworm space saver. 3 port honeywell valve. (new)
Honeywell room-stat (replaced like for like)

Whats worse is I still can't get heating to work properly and theres only 6 rads,
and return temps aren't good on any of the rads I can get warm or from hot water cylinder.

Could this mean the pump has now died, how can I check this?



help me

 

[giblets]

Sounds like a major air lock in the radiator circuit. I take it that the pump is working OK? Is the pump near the hot water cylinder and the H/W valve?

 

[voovon]

I tried all manner of airlock removal tricks yesterday for 5 hours but still have same problem.

Some silly bugger has concealed the pump above the kitchen making it totally inaccessable, the kitchen is an offshot and is also where boiler is,
I will expose tonight and try venting/hitting with a hammer.

Didn't really want to rip the kitchen panelling down but looks like i'll have to.


real tears this time

 

[voovon]

I ripped down the kitchen ceiling to get to the pump, bled it, and wahey!
Heating works now.

Just need to get to the bottom of the room stat always making boiler fire up problem now.

Seems like a wiring problem to me,

my honeywell stat is wired as follows;

T6360B
Terminal one = red wire (live)
Terminal two = black wire (neutral)
Terminal three = black wire, was careful not to mix up 2 and 3 when changed stat,

Noticed one of the black wires goes to white honeywell zone valve wire, is this correct?

Also read on stat instructions;

T6060 Replacement
For Central Heating applications up to 6 A., use T6360B

For applications between 6A and 10A, again use T6360B, but without the neutral connection. (See note regarding neutral connection.) note says "A neutral connection must be made to terminal 2 when the heating load is less than 6 amps".

How do I find out what amp the heating load is on my system?

 

[giblets]

If it's a bog standard heating system (which it sounds like) it will be less than 3 amps.

 

[gas4you]

White wire on honeywell valves is not normally used on pumped sytems, this is usually just for gravity systems. Return live off stat would normally go to brown on zone valve.

Is this fully pumped or gravity

 

[voovon]

Its fully pumped, with one, three position zone valve.

 

[voovon]

My honeywell mid position zone valve has five wires as follows.

Blue (connects to neutral in wiring centre)
G/Yellow (the earth)
White (connects to one of the black room stat wires, terminal 3)
Grey (connects to cylinder stat in wiring centre along with another wire which
should go to programmer)
Orange (connects as live to cylinder stat, boiler and pump)


It has occured to me, could this be a programmer fault? is the programmer not sending signal to switch off and thus room stat can re fire boiler?

(even though heating light on programmer turns off when switched).

 

[MANDATE]

I can't see how the programmer can be blamed.
The motor /valve operates over two halves of the full range. The first half is due to the room stat which if operating correctly supplies power to the white wire. This results in two electrical supplies going to the motor.
They can be thought of as a 'driving voltage' and and a 'holding voltage'
At mid position microswitch A is triggered and the driving voltage is dropped and 'holding voltage' remains to hold valve at mid position.
Now it all depends if HW is switched off or if on it may be satisfied.
If there is no call for HW, power is supplied to the grey wire from either cylinder stat or progammer HW OFF.
If the grey wire is live, then it takes over from the white wire at mid position and drives motor and valve to CH positon.
This also means that microswitch B is triggered and power to supply the holding voltage is now diverted out through the orange wire to fire the boiler.
It would appear most problems relating to these valves are either the motor or the microswitches.
You should be able to hear or watch the motor/valve move. If your satisfied it is moving to CH positon you can test for voltage on orange wire. (you can probabley remove the head for testing)
A test on white wire will confirm if room stat is working as you turn stat up and down.
The boiler can only be fired by one of two ways. Through the cylinder stat for HW and HW/CH shared. through the motorised valve for CH only

 

[voovon]

Thanks for your reply,

An electrician told me I should remove the neutral from the new honeywell thermostat, as it is no longer needed.

I will try that when I have time, unless anyone knows a reason I should not...

 

[voovon]

Sorted now!
Tried removing the neutral but that wasn't it.

A friend had an old programmer front same as mine, I switched it and now everything works fine!