hot water and heating in reserve

[carpetkarl]

Having changed the motorised port as per the old one, the heating now comes on when you push the hot water button and vice versea.
Motorised pump is not underside down and wires are as they were before, so how can this be?
I am totally confused and have check the wiring diagram and everything seems as it should be, but the hot water and heating are in reserve.
main problem is the hot water tank termostat now controls the CH, and thhe room thermostat contraols the hot water, so I need to find out what I did wrong.
HELP PLease

 

[mogget]

I'm assuming this is a 3-port valve.

It sounds like it has been fitted physically the wrong way round, ie hot water port connected to heating, heating port connected to hot water.

What is the make and model of the old and new valves?

 

[carpetkarl]

Its a sunvic sdmv 2304 and it replaced a Myson act 322, (or it might be MPE322).
Its not fitted upside down it is right, I just checked yet again, but if I did turn it upside down would this correct evrything

 

[D_Hailsham]

Its a sunvic sdmv 2304.

That's a motor on/motor off valve. Most valves are motor on/spring off. There have been concerns about their reliability.

It's not fitted upside down it is right, I just checked yet again, but if I did turn it upside down would this correct everything

Not upside down but the wrong way round! The three ports are marked A, B and AB. AB goes to the boiler/pump; A should go to the radiators and B to the HW cylinder.

 

[carpetkarl]

AB goes to the boiler/pump, A goes to CH and B goes to HW, thats what I got and thats how its fitted. The CH is the pipe that enters at base of tank and comes out half way up, but it still works vice versea, so it I flip the motor 180, it should work as it should do.

Am I right?

 

[mogget]

HW is hot water
CH is central heating

The pipe that goes into the cylinder is part of your HW circuit
The CH (radiator) circuit does not go near the cylinder

 

[carpetkarl]

I thought the CH pipe went inside the cylinder at the base and came out near the middle. The water went in the base and the hot water rose out of the top of the cylinder.

Have I got it totally wrong, if so why are there 4 pipes going into the cylinder

 

[Agile]

I thought the CH pipe went inside the cylinder at the base and came out near the middle. The water went in the base and the hot water rose out of the top of the cylinder.

Have I got it totally wrong, if so why are there 4 pipes going into the cylinder

How can you imagine that a Cewntral Heating pipe should ever go to the cylinder ???

Only a hot water pipe should go to the cylinder.

Dont you think that you need a p[rofessional.

If your motor valve is indeed a motor on/motor off, then its the wrong type.

Where did you get it and why did you apparently get the wrong type?

Tony

 

[mogget]

I thought the CH pipe went inside the cylinder at the base and came out near the middle. The water went in the base and the hot water rose out of the top of the cylinder.

Have I got it totally wrong, if so why are there 4 pipes going into the cylinder

I don't think you've got it completely wrong, but you do seem a bit confused about the names of the different parts.

Inside the hot water cylinder is one of these

Untitled

• mogget
• 21 May 2009
• 1

This is the coil, and is connected to the boiler HW circuit.

The four connections to the cylinder are

Untitled

• mogget
• 21 May 2009
• 1

Cold feed and hot water outlet - fresh water from the mains.
HW flow and return - water from the boiler.
The two lots of water do not mix, but heat can flow from one to the other.

By convention, HW refers to hot water for the taps, and CH refers to the radiators.

 

[carpetkarl]

thanks mogget that explains it. The hw flow and return it what I thought was for the rads, this info given to me by my plumber friend.

Agile,
the Sunvic is compatible with the myson according to the sunvic wweb site, and I never thought the CH went into the cylinder, I thought it cooiled through, but that appears to be the HW flow and return

 

[Agile]

If Hailsham is correct, and he usually is, then it is a motor on/motor off.

They are not direct replacements for a "standard" spring return type which the previous valve seems to have been.

Tony

 

[D_Hailsham]

They are not direct replacements for a "standard" spring return type which the previous valve seems to have been.

Yes they are! From Sunvic's website: "MoMo valves can directly replace all other spring return valves and are compatible with standard Y and S plan type controls systems."

The Sunvic Patent says that one of the objects was to make it interchangeable with a spring closing valve, so exactly the same wiring is used for a MOMO mid-position valve as for a spring return one.

The only drawback (apart from reliability) is that they do not produce a diverter (W Plan) valve.

 

[carpetkarl]

so the valve is ok,
I have it 180 around the wrong way,
You guys learnt something new, (sunvic are compartable),
what a w plan?

 

[mogget]

what a w plan?

Y plan - mid position valve - heating, hot water or both at the same time.
W plan - diverter valve - heating or hot water, but not both at the same time. Priority decided by system wiring.

 

[glasgowgas]

They are not direct replacements for a "standard" spring return type which the previous valve seems to have been.

Swing and a miss!!!!!!!!!!!!!!!!!