what system and poss iffy diverter

[dormermike]

Hi

Having decided to keep my boiler.. ideal mexico2.. i would like to fully understand my system so was hoping for some help pls.

Ive attched some pics for reference.

I think its a honeywell Y plan, is that correct? What are the three pipes beneath the pump that appear from the floor... I thought the centre one was from boiler, but not so sure now.
Also not sure what that cable is that runs down nr centre pipe?

Sometimes with HW only, the rads warm up... Iffy diverter from reading elsewhere. On Hw only the lever has no resistance between auto and man. On CH only there is resistance halfway.. is that sound about right?

Thanks

Untitled

• dormermike
• 20 Aug 2011
• 4

Untitled

• dormermike
• 20 Aug 2011
• 3

[/quote]

 

[Steve]

Your system looks identical to mine. All the following is based on my non-professional observation of my system.

It sounds like the 3 way valve (shiny metal thing where the pipes tee above the pump) is knackered. I had the same problem (the benefit is that you get piping hot water during the winter all the time! Though this will cost you money). Didnt need to drain down - the engineer had a "bung" that he fitted into the F&E tank to stop any feed.

The grey cable looks like the supply, and should have a switch on it somewhere, to isolate the system when nessecary.

The other 2 cables out of the wiring box will go to a thermostat and a timer somewhere. Mine is all in the same area. Perhaps you dont have a thermostat? As one cable will go to the boiler.

Its nice someone has fitted bleed valves into the two pipes off the 3 way - mine doesnt have these and after its been drained down, it makes a terrible noise because air is trapped in the top of the cylinder coil. Takes a good few days of use to loose this air.

The pipe coming off just below the pump - if it goes up, this will be the feed from the F&E tank (I think).

The right hand pipe going down is the supply to the radiators, and the left pipe is the return from the cylinder coil and will return to the boiler, after teeing back with the radiator return.

 

[MANDATE]

The lever on the side of valve is provided for the purpose of filling the system. With all power removed from system, the valve returns to its rest position (which is Hot Water) by means of a spring. So when refilling, water is restricted from the Heating side (causes air locks).
So the lever engages with the quadrant and moving it turns the motor.
You have to place lever in the latch (man),which holds valve at mid position and after filling it is unlatched (auto).
So with valve in HW position there will be resistance when pushing lever.
If valve is in mid position with system on, the lever will be loose if moved between HW and CH.
If valve is in CH position with system on, the lever again will be loose when moved.
You can use the levers resistance to prove if the valve has moved away from HW or not. It can be used on the latch in order to get some HW and CH if the motor is faulty, but this has restrictions because as soon as HW is satisfied the cylinder stat shuts the boiler down, whereas under normal operation it would move to CH but with duff motor it can't do that.

 

[MANDATE]

For the 'Y' plan to operate there has to be both a cylinder stat and a room stat.
The system has to recognize when either HW or CH or both is satisfied in order to move the valve to the correct position or close the boiler down.

 

[dormermike]

The grey cable looks like the supply, and should have a switch on it somewhere, to isolate the system when nessecary.

The other 2 cables out of the wiring box will go to a thermostat and a timer somewhere. Mine is all in the same area. Perhaps you dont have a thermostat? As one cable will go to the boiler.

Thanks for the info.

The black and white cables i've identified, but there are x3 grey cables.. one has a red tape around it (top left one, tape not visible in pic) which I guess could be power... I don't have a room thermostat but i guess the other two could be boiler and programmer?

I suspect the system had a thermostat at some point, I wonder if one of those cables doesn't go anyway (yikes).

I did take the cover off the box but it was a complete jumble - is that where a room stat would be wired into though?

 

[dormermike]

The lever on the side of valve is provided for the purpose of filling the system. With all power removed from system, the valve returns to its rest position (which is Hot Water) by means of a spring. So when refilling, water is restricted from the Heating side (causes air locks).
So the lever engages with the quadrant and moving it turns the motor.
You have to place lever in the latch (man),which holds valve at mid position and after filling it is unlatched (auto).
So with valve in HW position there will be resistance when pushing lever.
If valve is in mid position with system on, the lever will be loose if moved between HW and CH.
If valve is in CH position with system on, the lever again will be loose when moved.
You can use the levers resistance to prove if the valve has moved away from HW or not. It can be used on the latch in order to get some HW and CH if the motor is faulty, but this has restrictions because as soon as HW is satisfied the cylinder stat shuts the boiler down, whereas under normal operation it would move to CH but with duff motor it can't do that.

Thanks

Thats different to what i'm seeing - the opposite in fact. With my programmer set to HW, there is no resistance on the lever. With the programmer on CH only, I get resistance at about mid-way across the levers travel - is it wired in wrong?

 

[dormermike]

For the 'Y' plan to operate there has to be both a cylinder stat and a room stat.
The system has to recognize when either HW or CH or both is satisfied in order to move the valve to the correct position or close the boiler down.

I don't have a room stat but do have a cylinder stat. I think i will fit a room stat first and see how the system behaves.

Cheers.

 

[dormermike]

Also, what I dont understand is that with everything "cold" and switched off - when i turn the HW only to constant, the pipe on the right hand side is the first one to get warm... is that right?

 

[45yearsagasman]

It does not require a room stat to operate as it can be connected directly to the ch on from the programmer. I believe that fitting a room stat will not solve your problem as IMO your 3 port is where you should be looking.

 

[dormermike]

It does not require a room stat to operate as it can be connected directly to the ch on from the programmer. I believe that fitting a room stat will not solve your problem as IMO your 3 port is where you should be looking.

Ok thanks. Is there a way to confirm if whole head needs replacing or just motorised bit?