ESBE 3 port MOMO valve

[andrew1949]

Does anyone have any experience of the above valves?

We have a house with very long pipe runs and we have one of these fitted in 42mm pipe.

We have been experiencing some problems after fitting a new boiler, as the original had 2 switched lives (1 for CH, 1 for DHW) and we have been trying to configure it for a new boiler which only has 1 switched live.

The query I have is the valve has 5 wires, 1 neutral, 1 turns the valve clockwise, 1 turns the valve anti-clockwise. What do the other 2 do?

Any help gratefully received

Thanks

 

[oilhead]

Was this valve used on the previous boiler? What is the reference on the valve head?
Do you have a wiring diagram for the old system? What controls the valve, thermostat or time switch?
What are the old boiler and new boiler make and models?

 

[andrew1949]

Firstly many thanks for responding.

To answer your queries, this valve was installed with the original boiler and is an Esbe 12001100 65M

The old boiler was a Keston c55 and the new one is a Vaillant ecoTec Plus 64

The old system was controlled by a Horstmann 3 channel programmer, there was no roomstat fitted , just relying on TRV's and the boiler stat.

The system appeared to operate

Controller turns on DHW > Tank thermostat opens 2 way spring retun valve > turns on hot water circulation pump (separate to system pump in boiler> close ESbe valve to direct water to DHW circuit > sends switch live to boiler (note Keston boiler has 2 switched lives - this one obviously connected to the DHW side)

Controller turns on CH > Opens ESbe valve to direct water to CH circuit> switches on main circulation pump (this is separate to pump in boiler> sends switched live to boiler to CH side.

When the new boiler was fitted it could not be operated correctly, because they couldn't work out the wiring, the fact they had 2 switched lives for the old boiler but the new one only had one.

I would have thought they could have just joined them because the boiler doesn't need to know if you require DHW or CH , just to fire up and then it would be controlled by the tank stat or the boiler stat , as was the old one.

The biggest mystery to me is that you used to be able to have CH and DHW at the same time. I just wondered how it was wire as it appear you are sending it 2 conflicting commands , ie i to turn the valve clockwise and one to send it anticlockwise

Unfortunately as they have messed around with all of the wiring I can no longer trace how it was originally installed.

One final point the Esbe is a 3 port valve, but the T branch is blanked off, so only the 2 ends of the straight section are connected, it is fitted up stream of the main circulating pump.

There is a branch before it where the DHW flow if the valve is closed.

Hopes this helps explain the system

 

[oilhead]

The ESBE valve is effectively only a 2 port valve, so you can have DHW and CH at the same time, but not CH on its own. The spare 2 wires on the valve actuator could be an end switch that could be used to provide a switched live, or they may be a feed for a proportional controller. What is the reference of the actuator?

 

[andrew1949]

Hi thanks for the reply . The ref no on the actuator is Esbe 12001100 65M

We were able to achieve heating without DHW.

Hopefully, the rough sketch demonstrates how I assume the system works



Final question , as I said the old boiler utilised 2 switched lives - 1 to turn boiler on for CH, the other for DHW.

Clearly it makes no difference to the boiler as it just fires up, so can the 2 switched lives be combined, to the single connection in the new boiler?

Thanks

Andrew

 

[oilhead]

What is the 2 port valve on the cylinder? Is this wired to fire the boiler?
Looking at the Esbe web site, I would think the spare wires are for an end switch.

 

[andrew1949]

The bit I really can't get my head around is that the Esbe valve can be open when the wire from the programmer calls for heat , it closes when you energise the wire presumably from the tank stat for DHW

Yet there is a condition when it is open for CH and stays open even though you are also calling for hot water.

You could understand this if it was a mid-position valve but Esbe have confirmed it's only 2 position.

As I said the electricians have messed up the wiring trying to discover how the system works. Clearly they are not as accomplished as the original guy

Andrew

 

[oilhead]

I see from your diagram that what I took as a DHW circulating pump, is actually a primary pump on the DHW circuit.
Judging by your diagram, with nothing selected on the programmer, the ESBE valve and cylinder valve would be closed, and neither pump would be on. For DHW only, the programmer should open the cylinder valve and switch on the DHW pump and boiler. For heating only, the valve should open and the CH pump and boiler should switch. With both selected, you would have two open valves, and both pumps working. What we don't know is whether your original wiring incorporated any relays to prevent any backfeeds from energising items you don' want working. Does your cylinder valve incorporate an end switch, if so using that and the 'redundant' switch in the ESBE valve, you would basically be wiring as an 'S'Plan.

 

[andrew1949]

Many thanks for continuing to help me,

The 2 port valve on the DHW is a Boss Therm BZV2

This is from the blurb that came with the valve " When the brown wire is live, valve opens and the auxillary switch closes. When the auxillary switch is closed there is a circuit between the grey and orange wires."

I don't think there is an end switch, which had there been would have answered my query.

There do not appear to be any relays in the system, but as we were providing 2 separate lives to the boiler, perhaps that took care of it.

The Esbe valve stays in whatever position it was in until power is applied to either winding.

I just wish they would have left the original wiring intact if they weren't sure what they were doing

Andrew

 

[oilhead]

As I said earlier, your system is not very far away from an 'S'plan. You have end switches in both valves which can supply live feeds for your pumps and boiler. A competent heating installer should be able to sort it out for you. What response are you getting from your engineer? Have they given up?

 

[Terrywookfit]

It is not difficult to check if the two wires are connected to a switch.

 

[D_Hailsham]

The reason why there are separate switched lives for CH and HW is that the boiler can use weather compensation and Opentherm thermostats. Both of these features will adjust the boiler's flow temperature acording to demand. So when its freezing outside, the flow temp will be 75; but when it's 10C outside the boiler many only need to run at 50C. This is, obviously, not satisfactory when heating the hot water as the flow temperature needs to be at least 70C to bring the cylinder up to 60C.

Heating both CH and HW at the same time causes obvious difficulties, which is normally overcome by giving hot water priority, i.e when there is a call for HW the CH side is turned off temporarily and the flow temperature rises to the level set for HW. When HW has been satisfied, the system reverts to CH and the flow temperature is again controlled by the weather comp and/or Opentherm thermostat.

 

[D_Hailsham]

The old boiler was a Keston c55 and the new one is a Vaillant ecoTec Plus 64

The house (mansion?) must be extremely large. I do hope the installer carried out a detailed heat loss calculation and didn't just assume that the old boiler was correctly sized.

 

[andrew1949]

Thanks for the replies guys.

Firstly Oilman I misunderstood what you meant by "end switch". So yes there is a wire which is energised when the valve is open and can signal the Esbe valve and turn on the boiler.

As stated, this will energise the windings in the Esbe valve which will rotate one way, my problem is we could at the same time be calling for heat which would provide a live to the other winding in the valve.

As the system worked previously, there had to be some logic in the system to prevent this valve being energised by both lives at the same time.

There are no relays in the system, so I am wondering if the original electrician used some sort of output from the boiler?

We do currently have a working system which has come about by adding additional equipment and a ridiculous amount of time by the electrician, none of which I approved.

I am now being asked to pay for this.

If we go back to the beginning we had a working system, the quotation was to replace the boiler using the existing controls, the only issue was that the new boiler required 1 switched live and the old required 2.

Before messing with the original wiring, I thought it would have made sense to combine the feeds via a pair of relays.

D_Hailsham although the programmer allowed you to have DHW and CH at the same time the boiler itself gave priority to DHW, so I presume when the tank stat was satisfied, it switched over to CH (if the programmer was calling for both)

No detailed heat calcs were carried out by the second installer, although from experience we know that a boiler of this size is required.

Thanks guys for your continued interest

 

[fixitflav]

Heating both CH and HW at the same time causes obvious difficulties, which is normally overcome by giving hot water priority, i.e when there is a call for HW the CH side is turned off temporarily and the flow temperature rises to the level set for HW. When HW has been satisfied,

Just like in the old days of W-plan!