Heating Problem

[heatingeng]

We now think maybe its the Honeywell 4073 3 way valve, I have moved the lever to Auto (I think it was in the middle) and will see what happens in the morning with heating and hot water set both for 5.30am.

1. Are you sure it is a 4073 and not a 4044?

2. The lever is not a switch, it's there so the valve can be locked open when filling the system. To do this the lever is locked in the MAN position.

3. Can you check that the valve is the correct way round? The ports are labelled on the brass body. AB should go to the pump; A to the heating; B to the HW cylinder.

The valve may be sticking; you can check this easily:

Turn off power to heating system (not just at the programmer). This will reset the valve to the default position. The valve lever should be at the AUTO end.

Move the lever to the MAN end. You should feel a resistance as you are opening the valve against a spring.

When the lever is at the MAN end, let go and it should move back to the AUTO end, You should hear the valve closing.

Check again that the lever has resistance.

the system has always worked correctly in the past the guy has said and nothing has changed ?

 

[montys1]

Okay defintely a 4073A 1039 - stamped on the plate. All the ports are as you mentioned - AB - Pump A - Heating B - Cylinder.
Have cut the power, moved lever all the from Auto to Manual, resistance was there, let go - after 3 or so seconds it reset back to the middle. Tried again same result.

 

[montys1]

i leave my hot water on constat in my house .[/quote]

I might try that - thanks for all your input.

 

[MANDATE]

Could this problem be because of poor balancing between the HW side and the CH side. In the morning CH will be in demand and so will HW, having lost heat during the night. If there is more resistance on the CH side (which there will be unless controlled) then the easy route for the water is through the HW side.
Later the situation changes when HW becomes satisfied there is no flow at all through the HW side and all the flow is through the CH side.
I know sometimes a gate valve is provided on the coil outlet pipe, which acts like a 'lockshield valve' for balancing purposes.

 

[heatingeng]

Could this problem be because of poor balancing between the HW side and the CH side. In the morning CH will be in demand and so will HW, having lost heat during the night. If there is more resistance on the CH side (which there will be unless controlled) then the easy route for the water is through the HW side.
Later the situation changes when HW becomes satisfied there is no flow at all through the HW side and all the flow is through the CH side.
I know sometimes a gate valve is provided on the coil outlet pipe, which acts like a 'lockshield valve' for balancing purposes.

this is proberly the case here i would think .thats why i said about leaving water on constat as this would solve the problem without the need to mess about with the system

 

[D_Hailsham]

Could this problem be because of poor balancing between the HW side and the CH side. In the morning CH will be in demand and so will HW, having lost heat during the night. If there is more resistance on the CH side (which there will be unless controlled) then the easy route for the water is through the HW side.
Later the situation changes when HW becomes satisfied there is no flow at all through the HW side and all the flow is through the CH side.
I know sometimes a gate valve is provided on the coil outlet pipe, which acts like a 'lockshield valve' for balancing purposes.

This is probably the case here I would think. That's why I said about leaving water on constant as this would solve the problem without the need to mess about with the system

Even if you leave the water on constant at the timer, the cylinder thermostat will still be working. When the temperature of the water in the cylinder has dropped sufficiently, the motorized valve will move so the boiler water circulates through the cylinder coil and you are back where you started.

The only way you can make sure heating and hot water do not clash is either to have them at separate times or to have a diverter valve (V4044C) with hot water priority.

 

[heatingeng]

Could this problem be because of poor balancing between the HW side and the CH side. In the morning CH will be in demand and so will HW, having lost heat during the night. If there is more resistance on the CH side (which there will be unless controlled) then the easy route for the water is through the HW side.
Later the situation changes when HW becomes satisfied there is no flow at all through the HW side and all the flow is through the CH side.
I know sometimes a gate valve is provided on the coil outlet pipe, which acts like a 'lockshield valve' for balancing purposes.

This is probably the case here I would think. That's why I said about leaving water on constant as this would solve the problem without the need to mess about with the system

Even if you leave the water on constant at the timer, the cylinder thermostat will still be working. When the temperature of the water in the cylinder has dropped sufficiently, the motorized valve will move so the boiler water circulates through the cylinder coil and you are back where you started.

The only way you can make sure heating and hot water do not clash is either to have them at separate times or to have a diverter valve (V4044C) with hot water priority.

i dont agree .
if you leave the water on constat it should never cool down ?
if you fit a valve with hot water priority then it would be worse.
but as this is a general customer this is what i would advise because its easy and they dont have to start messing with controls.

 

[D_Hailsham]

Even if you leave the water on constant at the timer, the cylinder thermostat will still be working. When the temperature of the water in the cylinder has dropped sufficiently, the motorized valve will move so the boiler water circulates through the cylinder coil and you are back where you started.

The only way you can make sure heating and hot water do not clash is either to have them at separate times or to have a diverter valve (V4044C) with hot water priority.

i dont agree .
if you leave the water on constant it should never cool down ?

A cylinder stat has a temperature differential of about 10°C. So, if you set it to 60°C, the stat will not start heating the cylinder until the hot water temperature has dropped to 50°C. It will stop when the temperature reaches 60°C.

Every time the HW temperature drops to 50°C the cylinder stat will close the CALL contact and one of two things will happen: if heating is not running, the valve will be in HW only (port B open) so the boiler will light via the cylinder stat; if heating is running, the valve will move from heat only (port A open) to mid-position (A and B open) and the boiler will be lit via the cylinder stat.

 

[montys1]

Okay - last night I reset the programmer so that hot water comes on at 4.30am and off at 5.30am then heating on at 5.40am and off at 7.30am.
I woke up to a very toasty house and not an icebox like it has been for the last week!

Thanks to all for your suggestions and help - appreciate it.

Since last night I have changed the timings for the last time:-

Heating 5.40am - 7.30am 16.00 - 18.00 19.30 - 21.30

Hot Water 12.00pm - 13.00 17.30 - 18.30 21.30 - 22.30

Now I can sleep through to 5.40am without any noise, plus having the hot water on until 22.30 means if i am not having a shower there should be enough hot water in the morning for a quick wash and a shave!

**Toying with idea of getting a free no obligation quote from Southern Electric who with the government scrappage scheme (our Mexico 2 is eligible as its G rated and fitted in 1993/1994) plus their extra £400 scrappage means £800 towards a boiler - if it came to that**