Ah it seems never ending with domestic questions!

 

I have a Vaillant ecotec Pro 28 which I had installed at the end of 2011. Up to now its been perfect never a bother etc. However its developed a weird issue today.

 

Just to clarify, heating and hot water worked perfectly on Monday, I went away for work until Wednesday night. No need for hot water until the Morning but the heating was fine on wednesday.

 

Turn the shower on this morning, Stone cold its a thermostatic one run from the boiler, so I checked a hot tap in the bathroom, also stone cold However the heating was working completly fine.

 

I did take a quick look at it and it was almost as if it was simply ignoring the request for hot water.

 

I looked into it a bit more tonight when I got in from work, looking at the display and the "S" codes it gives, it goes through S1, S3 then S4 for heating fine, these vaillant boilers have a warmstart hot water function, I actually turned that on accidently hot water kicked into life, I checked it through a tap in the bathroom and it was fine. Perfect I thought, solved it.

 

Went for a shower just before and the swine just wouldnt go warm, although a vast improvement over this morning - managed to have a luke warm shower.

 

I left it running after and went down to have a look at it and it had heated the water to 45*c, but refused to do anymore - I think this is because the warm start feature is set at 45*c so its preheating to that, incidently its "S" codes are 20-24 as expected by the manual.

 

I turned warmstart up, and it went straight back to heating again (S.4) I've tried turning it of and on, and also tried doing the reset button but neither have helped.

 

Basically for whatever reason I don't think its seeing the flow of water through the heat exchanger and so doesnt realise it needs to heat water (however the actually ability to heat water seems fine as the warmstart thing works great)

 

Does anyone have any experience with Vaillants as to how I can fix this/get this fixed and if its going to cost me a million pounds or not :)

this could be a problem with the three way valve

The valve should have a wind on which is located on the side off it a little black lever it wont damage anything just push it forward gentle

oh doh its a combi

oh doh its a combi

 

Yeah it is a combi, its almost as if the stupid thing thinks its a system boiler actually but having been through the"user guide" and the "installation guide" that doesnt appear to be possible.

 

I do wonder there must be some sort of flow sensor in there that isnt working. Drives you mad, as of course its 4 months out of warranty...!

thermocouple I think inside maybe faulty!!

can give you a definitive answer in the morning, as our gas guy is a Vaillant engineer, we install pro 24 and pro 28 in our property's. usually something to do with blocked pressure pipe to the visual pressure gauage, or one of the many engineer settings.. drop me your mobile via pm and will call you tomorrow.

stu

Cheers guys.

 

However, I've done some more digging and it looks like the hot water flow sensor, went through the diagnostic and with a hot tap running the flow sensor is showing 0 liters a minute which I think is showing that the sensor simply isnt seeing the movement of water.

 

By turning the warmstart feature on it will allow me to have a small amount of hot water which is better tha nothing. Stu I have sent you my mobile number :)

chris

 

find the flow sensor , take off the connector , clean it, tap the flow sensor, put the blade of a screwdriver on it and tap the handle of the screw driver to shock the flow sensor if it is stuck, turn off the boiler power supply and wait 30 minutes,

 

re instate the flow sensor connector and re energise the boiler, ensure the presure on the gauge is in the green sector , if not then purge with the bypass valve to get the pressure in the green sector, check fault codes , if this is not flow related or working then possibly its the pressure non return valve passing causing the issue

 

Steve

if you do have to have an engineer out, try british gas website first and see if they still do the one price fix, it used to be about 160 quid, if its a 60 quid your unlucky but if its more then you have scored

The Vaillant combi I have usually plays up in strange ways when the battery is low in the timer. Doesn't seem related but I guess you've got a wireless one so might be worth a punt.

I had similar intermittent problems with my valliant boiler for ages. I replaced the diverter valve because it was leaking and never had a problem since. The valve cost me £70 of ebay.

I kept losing pressure on mine and was topping it up practically on a daily basis.

 

One day in the shower the temp was up and down.

 

Went on the old tinternet and worked out it needed repressurising, so out came the bike pump and as been much better since with hardly any pressure drop and the water is very stable.

 

You don't mention pressure Chris, may or not be relevant but thought I'd post, may help, may not :thumbup1:.

chris

 

find the flow sensor , take off the connector , clean it, tap the flow sensor, put the blade of a screwdriver on it and tap the handle of the screw driver to shock the flow sensor if it is stuck, turn off the boiler power supply and wait 30 minutes,

 

re instate the flow sensor connector and re energise the boiler, ensure the presure on the gauge is in the green sector , if not then purge with the bypass valve to get the pressure in the green sector, check fault codes , if this is not flow related or working then possibly its the pressure non return valve passing causing the issue

 

Steve

 

Cheers mate I had a bit of a look today and found the flow sensor but decided not to mess to much. As it happens I have a plumber coming tomorrow to move a gas supply to the boiler so it can be recessed for the new kitchen/diner im doing so he is going to take a look. Bloody thing!

 

if you do have to have an engineer out, try british gas website first and see if they still do the one price fix, it used to be about 160 quid, if its a 60 quid your unlucky but if its more then you have scored

 

Yeah its a fair point mate, I'm conviced its this sensor though which is only £20 of a part and doesnt look to bad to fit after a quick glance - just meant draining everything etc.

 

The Vaillant combi I have usually plays up in strange ways when the battery is low in the timer. Doesn't seem related but I guess you've got a wireless one so might be worth a punt.

 

Its on a wireless thermostat so yeah could be as I said its the hot water that is ondemand as it were thats the problem, the heating works perfectly.

 

I had similar intermittent problems with my valliant boiler for ages. I replaced the diverter valve because it was leaking and never had a problem since. The valve cost me £70 of ebay.

 

This is the other potential cuprit, but as it will actually heat water fairly well on the warmstart/preheat mode I dont think its that. I did also do the diagnostic and could hear the diverter valve moving from position to position and the display was reporting the correct position information as well so I'm less convinced thats the issue at the moment.

 

I kept losing pressure on mine and was topping it up practically on a daily basis.

 

One day in the shower the temp was up and down.

 

Went on the old tinternet and worked out it needed repressurising, so out came the bike pump and as been much better since with hardly any pressure drop and the water is very stable.

 

You don't mention pressure Chris, may or not be relevant but thought I'd post, may help, may not :thumbup1:.

 

Cheers mate, yeah although it requires the heating to be full and pressurised that isnt the issue I dont think, the heating holds a perfect 1.5 raising to 1.8 when its warm and dropping back to 1.5 when cold. I've had to drain and refill the system a few times recently as we have been doing alot of work moving and adding radiators in places around the house. As I said though the heating is working great, just the hot water being a total bellend! :)