Vailliant sustain 418 heat only problem

[diycooper]

Well, that's odd, because originally boiler would not fire for hot water. Can you post a photo of the pcb wiring and the front of the boiler? As per @Mottie - It should be your installer sorting, not you.

Yes l thanks I agree it should be installer. It's in a rental also so bit more of a problem.

I'll get a picture when can attend .

Sounds unlucky but if wired right at boilor and 240 v is not switching on and off at boilor on ch and hw so permanent live ( which I don't know is case yet).

Could the 3 port head of gone causing a permanent live.

So this would need checking the orange wire on y plan is switching 230v to 0 when turn controls on and off ?

 

[Johntheo5]

Here are two schematics of a Y plan, in both, the switched live starts both the boiler and the pump, very common in oil fired boilers with no pump overrun, but most, if not all (now) Gas fired boilers, the switched live just goes to the boiler which will have a permanent live to do the required switching, pump overrun etc.

 

[CountryFan]

Sounds unlucky but if wired right at boilor and 240 v is not switching on and off at boilor on ch and hw so permanent live ( which I don't know is case yet).

Could the 3 port head of gone causing a permanent live.

Potentially, but as you say unlucky.

So this would need checking the orange wire on y plan is switching 230v to 0 when turn controls on and off ?

Yes, check live feed back to boiler

 

[diycooper]

Potentially, but as you say unlucky.

Yes, check live feed back to boiler

So I just attended the property original installer got a vailliant heating engineer to attend. Boilor was wired correct.

Before the Vailliant engineer got there I turned heating on and highered stat. Boilor fired up then I turned off heating and boilor turned off.

I then turned hot water on cylinder was cold boilor fired up pump came on cylinder heating up. I lowered stat down on cylinder pump turned off.

Highered stat on cylinder back up pump kicked in cylinder heated up then pump turned off when up to temp.

Engineer said wasnt doing that yesterday.

Vailliant engineer stated there no cable from y plan to boilor for pump and on Valllliant you need that or can gdt F83.

Original installer said it was F83 yesterday . ( First time I found out about F83)

I paid Vailliant engineer today. Now have to pay someone to install cable from y plan for pump to boilor and connectvat boilor.

I guess even if this was picked up by original engineer install would of been more for extra cable run.

 

[CountryFan]

Vailliant engineer stated there no cable from y plan to boilor for pump and on Valllliant you need that or can gdt F83.

Original installer said it was F83 yesterday . ( First time I found out about F83)

New one on me, but I only deal with combi’s mainly.

I paid Vailliant engineer today. Now have to pay someone to install cable from y plan for pump to boilor and connectvat boilor.

Did you agree to Vaillant engineer? If not, should be installer paying imo.

I guess even if this was picked up by original engineer install would of been more for extra cable run.

Probably, but you have had to pay the Vaillant engineer plus a site visit.

 

[diycooper]

New one on me, but I only deal with combi’s mainly.

Did you agree to Vaillant engineer? If not, should be installer paying imo.

Probably, but you have had to pay the Vaillant engineer plus a site visit.

No I never agreed but I met at property then original engineer asked did I have money to pay him.

Not sure if the original engineer was going to knock it off his install but in all honesty I couldn't be bothered arguing.

Tbh the Vailliant engineer only asked for £50. But he just told us about pump wire as by time he got there I had checked system.

I just want it sorting as tennant on holiday and back Monday so at least I can get cable in.

But then I have to pay Vailliant engineer to connect it at y plan and boilor.

Just want it sorting. All in all original engineer should of knew potentially about cable. Then I could of got it in before he started and not had to pay Vailliant engineer twice.

 

[diycooper]

New one on me, but I only deal with combi’s mainly.

Did you agree to Vaillant engineer? If not, should be installer paying imo.

Probably, but you have had to pay the Vaillant engineer plus a site visit.

Yes regarding wire for pump it's in vailliant instructions.

I think my installer does not install many heat only..

Original engineer never charged me alot. £400 for install with him supplying pipe.

Then I gave Vailliant engineer £50.

Maybe another £50 to connect up.

So £500.

Plus electrician for cable run maybe £120.

So all in all £720

But I feel I had took responsibility in end and all the visits I've had to do.

 

[diycooper]

New one on me, but I only deal with combi’s mainly.

Did you agree to Vaillant engineer? If not, should be installer paying imo.

Probably, but you have had to pay the Vaillant engineer plus a site visit.

I also supplied boilor .

I got boilor and flue for £1123.82

Full install cost £720 with extra cable connectv.

So total £1843

Just want the headache gone.

 

[Johntheo5]

I think it should be wired in this manner??

 

[diycooper]

I think it should be wired in this manner??

View attachment 420274

I believe the pump goes into x14 on boilor not sure how on y plan Im not up on them

 

[Johntheo5]

Have you got a permanent live to the boiler?, if so and the Vaillant engineer is correct, "Vailliant engineer stated there no cable from y plan to boilor for pump and on Valllliant you need that or can gdt F83." then that permanent live will only logically be used for frost protection. If no permanent live supplied or required (for pump overrun) then the Y plan switched live just starts/stops the boiler & circ pump simultaneously. You should only get a F83 (assuming circ pump OK) if the boiler is firing without the pump running or if it starts firing before the pump starts or stops firing after the pump stops.
How old is the circ pump?.

 

[diycooper]

Have you got a permanent live to the boiler?, if so and the Vaillant engineer is correct, "Vailliant engineer stated there no cable from y plan to boilor for pump and on Valllliant you need that or can gdt F83." then that permanent live will only logically be used for frost protection. If no permanent live supplied or required (for pump overrun) then the Y plan switched live just starts/stops the boiler & circ pump simultaneously. You should only get a F83 (assuming circ pump OK) if the boiler is firing without the pump running or if it starts firing before the pump starts or stops firing after the pump stops.
How old is the circ pump?.

There a permanent live neutral and earth then switch live on rt.

The boilor switching on and off now. I think the f83 happens as if the pump not connected to boilor the two flow sensor do not read corrextvand also the Vailliant xannot keep pump running once demand stops for like 5 m

Have you got a permanent live to the boiler?, if so and the Vaillant engineer is correct, "Vailliant engineer stated there no cable from y plan to boilor for pump and on Valllliant you need that or can gdt F83." then that permanent live will only logically be used for frost protection. If no permanent live supplied or required (for pump overrun) then the Y plan switched live just starts/stops the boiler & circ pump simultaneously. You should only get a F83 (assuming circ pump OK) if the boiler is firing without the pump running or if it starts firing before the pump starts or stops firing after the pump stops.
How old is the circ pump?.

Not sure I'm understanding so forgive me if not.

Boilor is wired correct with live neutral earth switch live ( rt). No other separate cable from x14 on board to y plan pump.

So I believe as pumps run from y plan direct not the boilor then sometimes the sensor in boilor cannot read cirrect and get f83 and also the boilor might not keep the pump running for 5 mins after demand has stopped so this can cause f83.

Pump working OK turning on and off correct. It's just not wired direct which I will need to rectify to avoid f83 intermittently coming on.

It never f83 when I was there today but I guess it will once run for alot longer and the pump needs wiring to boilor as vailliant instructions say it needs too.

 

[diycooper]

Have you got a permanent live to the boiler?, if so and the Vaillant engineer is correct, "Vailliant engineer stated there no cable from y plan to boilor for pump and on Valllliant you need that or can gdt F83." then that permanent live will only logically be used for frost protection. If no permanent live supplied or required (for pump overrun) then the Y plan switched live just starts/stops the boiler & circ pump simultaneously. You should only get a F83 (assuming circ pump OK) if the boiler is firing without the pump running or if it starts firing before the pump starts or stops firing after the pump stops.
How old is the circ pump?.

The inage shows it can f83 can happen due to incorrect temperature sensor reading which can be caused by the boilor not controlling pump correct as will be in my case as its not wired to boilor like it should.

 

[Johntheo5]

If, after the boiler (burner) shuts down when either its switched off manually or is shutdown by the (last) room stat or cylinder stat and if the pump runs on for a few minutes and then stops, then the system is wired correctly and installing this other wire directly won't cure a F83 problem IMO, buts lets see.

 

[diycooper]

If, after the boiler (burner) shuts down when either its switched off manually or is shutdown by the (last) room stat or cylinder stat and if the pump runs on for a few minutes and then stops, then the system is wired correctly and installing this other wire directly won't cure a F83 problem IMO, buts lets see.

THis is logic apparently behind it.

The Sustain 418 is designed so the boiler can keep the pump running for a short period after the burner switches off. That pump overrun carries residual heat away from the boiler and helps stop the boiler getting too hot internally.

If the pump is powered only from the old Y-plan wiring, the Y-plan can shut the pump off as soon as demand ends. If the pump is connected to the boiler’s pump output, the boiler decides when the pump stops, so the overrun can work properly.