Vaillant ecotec 837 Plus losing pressure

[skykit]

Hi all,

I suspect the end result here will be...get someone in ! But I would like to maybe use this to check the basics first so a. I'm not missing anything obvious but b. Unfortunately I don't have much luck with any of the trade around us so I prefer being armed with as much information as I can.

In short, I live in a "new build" of 7 years old and we had the Ecotec 837 Plus installed as part of the house.
We have not had many issues apart from maybe once or twice a year topping it up due to the low pressure error.

I've also had a local company service it annually up until lockdown at which point it was missed for 2 years due to lockdown and a lockdown baby
And with the excuses over...

Issue:
Recently I have noticed I am topping it up using the two valves under the boiler a lot more than 1-2 times a year.
More recently, it has needed it once a week.
Initially I blamed it on the cold spell we've been having because where the boiler is on and off during the day, the cold spell has meant we've had it on most of the day.

I have read a few threads on here and the one test/check seems to the be pipe leading outside. As it comes out in a carport, it is quite obvious if water is coming out of it or not which is where I have noticed the "block paving" directly under it and next to it (the exit of the pipe) has been wet.

Having said that, I am unsure if this is because I've been topping it up to a point maybe it goes too high?

Pressure-wise, I top up half way on the bar (sorry I did not check in bar)
When the heating is on, the most it got to was 3.0 however it seems to sit on around 2.6

Leaks: I can't see any. We don't have copper pipes so I can only go by feel of the carpet. They have some sort of plastic? pipe going into the rads which allow the rads to pop off and placed flat on the floor ...thats the theory anyway.
I'll check in the loft tonight as some pipes I know go into loft but I think they're just the ones that go into the towel rads upstairs and I would have seen the leaks

Other observations - and this could be in my mind but I feel maybe the rads are not getting as hot as quickly especially downstairs.
However we are fully smart-homed and not all rads always switch on whereas in the cold-spell, all have been fired up so maybe its just the load?

Air: Have gone through all the rads and no air in the rads

House size: 4 bedrooms, ensuite + bathroom + cloakroom
5 rads downstairs
5 rads upstairs
2 towel rads in bathroom/ensuite


Happy to check/test/run anything on the boiler if I am guided

Thanks in advance and apologies for the long thread - I know other threads seem to have almost no information so I thought I would give everything!

Note: It's not causing me major issues apart from the odd inconvenience of topping up due to the boiler switching off at 2am meaning on heat in the morning but house is largely ok containing heat.

Obviously I have taken note that the more I top up, the less the inhibitor in the system is working/is being diluted.

 

[skykit]

Should note, I am planning on getting either the company that usually look after it for servicing or go via Vaillant to service the boiler. I think the purpose of this thread is whether this sounds like a boiler issue or a plumber issue due to a leak in the system as opposed to boiler if that makes sense

 

[skykit]

I know there were no replies but hate not updating if there is a solution of sorts.

I ended up not using our usual local boiler service company on the basis their £114 charge was too much when compared to others at around £80-£90 and in the end, it was actually cheaper to get Vaillant out to do the service themselves at £89.

I mentioned while the boiler was working fine, it seems to require a fair bit of pressure topping up especially recently in the cold spell. As part of the service, the expansion vessel was checked and he found "it was completely flat" and most likely due to the fact I missed the last couple of services as topping up is part of it - And apparently it is this that will be related to the constant pressurisation of the boiler.

So there you have it - don't miss a service
Interestingly, my neighbour who has never had his serviced still only tops up twice a year.

Case closed for now.

Oh and I did raise the query about the chemical in the system given I was topping up a fair bit recently - apparently it was dip-tested and has come back fine.
I'll probably get the system re-chemicalised next service either way (if its good practice) given its been 8 years since the original fillup.