At the end of my tether with this Duo Tec.

[arran197]

I went to a 2 year old Duo Tec earlier in the year which wasn't working. The initial job was to replace a couple of leaking rad valves and re-fix a rad to the wall. It had been drained down by another engineer on out of hours call out. I replaced the valves, re-hung the rad and filled the system. It started leaking badly from the pipework under the floor. I capped it off as it needed re-piping and filled the system. Then the problems really began. The boiler was not circulating at all. It started banging and getting too hot as soon as it fired up.

It had a powerflush, it's had 2 prvs and a pump. Another engineer went out and cleaned out the filter on the return pipe. He said the boiler was working ok so left it. Now I've gone back and the filter was blocked up, but I couldn't unblock it, so I've taken it out completely.

I took out the diverter valve, but I', not sure it's the right one fitted! I can't remember what it should look like, but I'm fairly sure it should be the one with the ceramic frame, with it being a 2010 boiler. This is the one I think should be fitted Baxi Duotec 3 Way Diverter Valve Cartridge 720003100 | eBay

The one that is fitted has a single spindle fitted, which I'm sure is for the boilers with the bypass, rather than without. I'm normally good with Duo Tecs, but I'm not sure where to go with this one.

 

[mickie]

can you not just find the gas council number and give it to a merchant

 

[tom609]

i agree gc number then parts center or some other supplier

 

[Billy Bob Bob]

i agree wrong spindle fitted

 

[arran197]

Went back to this Christmas eve. I was convinced the wrong diverter valve had been fitted after having a good think about it when I left the job. So first thing I did, put my hand behind the diverter & felt the end of a 1/2" black iron plug! I fetched the correct diverter, whipped off the old one , also taking out the plate & pump. Plate was fitted about 4 weeks ago with the diverter & the wrong pump, 15-50 but should be a 15-60. Plate was full of black debris. I filled it with f5 %& left it. Fitted everything back & still no good. Very little circulation. Took off the auto bypass just in case, same. I filled it with cleaner & left it, hopefully the little bit of circulation will loosen it up. New rads, pipework & heat ex being fitted in the new year. Boiler has been installed on 12 year system which must not have been flushed correctly.

 

[gastec]

before changing the heat exchanger take it out of the boiler, get the garden hose on full pressure and jet the flow and return pipes in till the black flakes stop coming out, stick it back in the boiler and fit a magna clean to the return. ive done this on a few times on these type of heat ex and has worked every time

 

[arran197]

I won't be doing it I don't think. If I was working for myself & had the time, I'd certainly try it.

 

[arran197]

So, in the end my manager sent me back with a heat exchanger. Which is actually very easy to replace. Within 90 minutes it was back up and running. It's had some new pipework and new rads. Hopefully I won't be going back to it, fed up with the bloody place. Must have put 12 hours in to this boiler.

 

[herp_lee]

Check auto air vent isnt stuck shut. Sounds like it to me

 

[arran197]

Auto air vent wouldn't cause this problem. Was working anyway.

 

[herp_lee]

Not circulating properly, noise and overheating ? I have had it before on Baxi and it was the aav mate. In my case it was anyway

 

[arran197]

Ye, it's been an ongoing issue with this boiler since the beginning of 2012, which was an ongoing issue since 2008 when the first Duo Tec was installed to replace a dead Ravenheat. Then the Duo Tec was replaced with a new Duo Tec and then it happened all over again because some installer couldn't be bothered to flush the system. The should get the sack or the repair bill if they still work for the company.

I've had air in them before, but never known air to cause this kind of trouble.