ecotec plus 837 and Y plan !

[Lee4all]

Help peeps !
Customer has a vaillant 837 and decides they want a pumped shower for their main bathroom (5 bed, two bathrooms and an ensuite)
I fit the cylinder, shower, pump etc etc and then wire in the mid position valve ,cylinder stat, room stat and two channel programmer.
As in the linky http://content.honeywell.com/uk/homes/systems.htm

The problem is the boiler now constantly rotates to fault code s97 s98( flow/ return sensor check is running, demand (DHW or Heating is blocked) preumably the valve is either not opening fast enough or ??? the boiler then sits idle at code s53 .
Please can anyone give me a starting point to fault find TIA.

 

[EliteHeat]

Why did you not fit an "S" plan?

 

[Lee4all]

S Plan

Suitable for fully pumped installations with two primary circuits, usually one for heating and one for domestic hot water.
The DHW is not pumped on a 837!
Y plan
Similar to the W Plan but with the ability to supply both heating and hot water circuits at the same time, if required.[/u]

 

[gas4you]

S Plan

Suitable for fully pumped installations with two primary circuits, usually one for heating and one for domestic hot water.
The DHW is not pumped on a 837!
Y plan
Similar to the W Plan but with the ability to supply both heating and hot water circuits at the same time, if required.[/u]

No, but it is to your new HW cylinder, so therefore you have 2 pumped circuits.

Saying that Y or S plan should not make any difference if wired up correctly.

The auto bypass in the 837 should still give a circuit for the pump to circulate and the 3 port valve will always be open one way and should rest dead in DHW position.

 

[EliteHeat]

S Plan

Suitable for fully pumped installations with two primary circuits, usually one for heating and one for domestic hot water.
The DHW is not pumped on a 837!
Y plan
Similar to the W Plan but with the ability to supply both heating and hot water circuits at the same time, if required.[/u]

The reason that I would not fit a "Y" plan system to this or any other combi is that I wouldn't want stray or reduced voltages sent to the PCB.

It would have made much more sense to fit two zone valves and pick up the 230V from the PCB and let the zone valves relay it back.

 

[Lee4all]

Thanks for the input, i,m still at a loss though as what to do next.
If i am to get this system up and running i need to prove either the wiring/valve is faulty or i could even have a boiler fault!

 

[EliteHeat]

Remove all external control voltages and replace the bridge between T3 and T4 and see what it does.

 

[Lee4all]

Thanks for that i,ll give that a try, you thinking like me it could be the pcb !!!

 

[ChrisR]

Depends how you've wired it, but you could have the boiler OFF, ie the stat feed voltage from the boiler off, but still be getting mains back from your orange wire on the 3 port. That used to blow pcb's all the time, but sensible manufacturers have stopped it doing that. But I wouldn't be surprised if it still causes trouble.

Vaillant et al will give you wiring diagrams for things like that.

 

[simond]

As suggested, remove your wiring from 3 and 4 and replace with a link.

If the boiler works OK then the fault is not precipitated by the boiler.

The PCB in an 837 ecoTEC combi is the same as their system boiler eg:637. Therefore there should be no incompatibilities with a 3 port valve.

Have you ensured that the supply to your programmer permanent live is taken from pin 3 of the boiler? eg: NOT permanent live?

The Orange from the 3 port valve should then be into pin 4 on boiler.

 

[Lee4all]

Thanks for the help I have removed my wiring from 3 and 4 and replaced with a link.
Hot water ok on demand.

Wired in a Grasslin towerchron Qe1 to prove the heating all ok there as well , so it has to be my wiring of the mid position.
I've followed the wiring scematics in the link in my fist post and still no joy,

 

[Lee4all]

Can anyone help with a wiring schematic that will work ?

 

[Lee4all]

Can anyone help please?

 

[gas4you]

All I can suggest from afar is to strip out all of your wiring and start from scratch.

It may sound ridiculous and not meant to be personal, but are you colour blind so have got the valve wires wrong?

 

[simond]

The Honeywell diagram is wrong if it is a Vaillant.

Can you confirm that the power supply for your timer (and therefore the source for HW on, HW off, CH on) is coming from pin 3 of the boiler, NOT permanent live as shown on your Y plan diagram?