Vailant boiler help please!!!

[Absx]

Hi guys,
This Vailant boiler is driving me mad.
It’s a Combi

So for a few weeks the water hadn’t been getting very hot, it used to be scalding hot out the tap now it’s not like that. Then The water started going luke warm/hot etc during showers.

Now the pressure drops every 1-2 days and it needs topping up, when it works still the water pressure is much lower coming out of the hot tap that it used to be and the water not as hot etc as it used to be....

I don’t get paid till next month so I’m hoping this is something simple.

Vailant do a fixed price repair for £249 but it doesn’t. Include the expansion vessel or the Heat exchanger

I’m honestly confused what it could be

Thanks

 

[AGAS]

when was the last time it was serviced and what was done ?

you've got 2 problems going on i expect

 

[Absx]

when was the last time it was serviced and what was done ?

you've got 2 problems going on i expect

4 months ago, ‘strip and clean’ carried out

 

[AGAS]

do you live in a hard water area ?
i suspect you do

 

[Absx]

do you live in a hard water area ?
i suspect you do

Yes I think I do mate, kettle gets ruined so needed to have a ‘Brita filter kettle’

I’m in Northamptonshire

 

[Bobby21]

The lukewarm water may suggest a blocked plate heat exchanger.. the pressure dropping suggest a leak or the prv is leaking

 

[Absx]

The lukewarm water may suggest a blocked plate heat exchanger.. the pressure dropping suggest a leak or the prv is leaking

Hi mate, so do you think the Vailant £249 fixed price repair is the best bet?

It says inc all parts and labour except the ‘heat exchanger and expansion vessel’

Is the plate heat exchanger different to the main one?
https://www.vaillant.co.uk/homeowners/after-sales-care-and-servicing/repair/

 

[Bobby21]

What model of Vaillant is it?

 

[Absx]

What model of Vaillant is it?

Hi mate no model number written anywhere on it?

I fixed the pressure issue as found a heater was leaking so that’s one half resolved

The temp issue remains. If it’s the secondary heat exchanger I think I’ll just get Vailant to go look at it?

The water coming out the rad was BROWN and rusty disgusting! I bet that explains the boiler issue?

 

[Doggit]

If the rad water is brown, then the last engineer didn't check the system had enough inhibitor - so exactly what did he do. The water heater may well be calcified, and that can be descaled, but I suspect the thermistor on the water heat exchanger is also iffy, as that would explain the water getting scalding during showers, whereas the heat exchanger needing descaling would only cause a reduced water temperature.

If you explain the possible issues with anyone you speak to, they should give you a reasonably straightforward quote, but you also need to check that Vailant would also cover the issues under their fixed price scheme. Inhibitor, thermistor, and descaling.

 

[AGAS]

If the rad water is brown, then the last engineer didn't check the system had enough inhibitor - so exactly what did he do. The water heater may well be calcified, and that can be descaled, but I suspect the thermistor on the water heat exchanger is also iffy, as that would explain the water getting scalding during showers, whereas the heat exchanger needing descaling would only cause a reduced water temperature.

i suspect the domestic side of plate is limscaled up with the hard water hence causing poor hw flow , i very much doubt the problem is the thermistor .

the other problem is the expansion vessel ( re pressure or split bladder depending on the service that was provided ) i expect for which i don't think he would get very much value from vaillant services considering what they don't cover and also when they find the shyte system water then that visit would be very much more useless for which i rarely say regarding advising the public

 

[Doggit]

i very much doubt the problem is the thermistor

Then how do you explain the water temperature going lukewarm then hot during showering. If it just required descaling, then the temperature would only be lower than usual, not up and down. Is it possible that there's a thermostatic shower that's playing up in conjunction with the water being colder than usual.

 

[Absx]

Then how do you explain the water temperature going lukewarm then hot during showering. If it just required descaling, then the temperature would only be lower than usual, not up and down. Is it possible that there's a thermostatic shower that's playing up in conjunction with the water being colder than usual.

Hi mate I meant the water does luke warm then warm etc. But it’s always lower than it used to be? I’m just really confused how.
The Vailant fixed quote I thought would be the best best but if you think it just needs descaling I guess I could just ask local people who quotes

 

[Absx]

i suspect the domestic side of plate is limscaled up with the hard water hence causing poor hw flow , i very much doubt the problem is the thermistor .

the other problem is the expansion vessel ( re pressure or split bladder depending on the service that was provided ) i expect for which i don't think he would get very much value from vaillant services considering what they don't cover and also when they find the shyte system water then that visit would be very much more useless for which i rarely say regarding advising the public

Hi mate if the domestic side of the plate is limescaled then does that plate have to be replaced? Can it be cleaned?

Can you guys please give me a ball park figure for descaling something like that

Thanks in advance

 

[AGAS]

Then how do you explain the water temperature going lukewarm then hot during showering. If it just required descaling, then the temperature would only be lower than usual, not up and down. Is it possible that there's a thermostatic shower that's playing up in conjunction with the water being colder than usual.

tbh i may suspect the shyte system water isn't helping either but the limescale produces the effect also , also problems may exist with the shower/ cartridge.

this is a picture of a plate being affected by limescale alone which i see a lot where i live which reduces the hw flow also but descaling this plate is the way to go