Noisy 28 Cdi

[ChrisR]

Without Chris's tachometer that can be difficult to confirm. I wonder how it works?

SInce you ask, it has a rubber end, which I'm hoping I can add to or modify to poke through the screw hole on a grundfos type pump. Or you can remove the end to use it optically - would need a blob of tipp-ex or reflective tape. That would be better for fans.

If I can ever find all of, it, a dodgy pump, a dodgy fan, LCRQ meter, some capacitors, a mains lead, some time and a space on the kitchen table, it may be of some use to me one day. Right now it's probably in the 5ft high pyramid of boiler spares just behind me now.

 

[DP]

PVM what is the temperature differntial on flow and return to the rads at the boiler. Then, what is the temperature differential on flow and return on the plate heat exchanger (I would be looking for 20 degrees).

You have most likely already checked, but the pump should be on speed three. Pump is normally a 6m head pump.

I have in the past cleared systems where the water was clear, but plastic pipe related debris could plus a fitting that resisted mains pressure water.

If the plate heat exchanger offers any resistance to primary water flow, initially you will get the noise you refer to, followed by boiler cycling between hot and cold during HW demand. In all cases I have cleared systems using Fernox DS40.

Try changing the sensors over. Yesterday replaced a sensor on Baxi 105 to clear the fault. Sensor resistance 12k as per spec when cold. Was breaking down at higher temperature.

 

[PEDANTICVINDICTIVEMAN]

Thanks for the input DP, have tried all that, l am going to change the pump today, if this fails it will have to be worcester, not going to do very well out of this job by the looks of it as I have a no fix no fee policy, 2 tubs of x200, 6 hours and a 15/60 grunfoss, well if it dont fix !!!!!!!!booooooolllllllllllloooockkkkkkkks

 

[Agile]

If the pump does not fix it, just try about a quarter of a tub of DS40 in the boiler on its own with the heating isolated before you give up. Leave it in on DHW for at least 40 minutes switching to CH for the odd minute every five.

Using the X200 was a total mistake as its the wrong product and was left in for far too short a time.

I am pleased to hear that you also have a No Fix No Fee policy. We have had that for a long time but we do charge for diagnosing the problem and its then up to the client to decide if he wants it fixed, usually at just the extra cost of the parts.

Tony Glazier

 

[PEDANTICVINDICTIVEMAN]

This boiler has really ****ed me off, fitted new pump which has now made it quiet when running but bangs when demand has finished, I reckon the pcb pump overun has failed because pump doesnt run on after demand,(it does on CH) so now I have fixed half the probelm but not all of it, had enough now after all the time spent so going write off 2 tubs of x200, new sensor, new pump and 8 hours of labour, I am not willing to risk pcb cost as this boiler obviously has a grudge against me, told them to get Worcester and let me know whats wrong with the ****tin thing.

 

[Agile]

Boilers dont bear grudges, only installers!

So it seems the pump WAS running slow as Chris's taco think would have shown if only he could have found it.

Unfortunately, I am not that familiar with Worcesters when unable to see them in front of me.

One earlier model had a stat to give the pump over run and that often failed. Are you quite sure that on your model its the pcb which provides the over run?

Obviously its a different matter with a neighbour and you cannot expect to charge as much or even anything in some cases.

But you must weigh up not fixing it against your reputation and I would have thought replacing the PCB would be well worthwhile and then you can at least charge him for the bits i.e. pump and pcb. You will have to write off the X200 but that was the wrong stuff anyway. The time is irrelevant as you would have still been alive and probably posting here or some other unpaid activity.

Tony Glazier

 

[PEDANTICVINDICTIVEMAN]

When I phoned Worcester tech they said overun built onto pcb, I had allready looked on the spare parts list for an overun stat before asking.
I will not lose out too much as the customer always uses me for other jobs and has just bought another house for his parents and will want a lot of other work doing in the near future.
This doesn't affect my no fix no fee policy, I try to be fair to all my customers
and tell them straight if I am not familiar with there particular boiler whether it is an ancient beast or a new fancy thing.
I have a good reputaion and aim to keep it, you dont get given the keys to someones house while they are away for 2 weeks and paid up front if your not straight with people.

 

[ChrisR]

At least you can charge rrp for the pump- about £80!

 

[COG]

Pen..... You suspected a restriction in the gas to water heat ex, thats prob the fault as you may have noticed from my previous posts i only work on Worcesters,the g/w tends to get blocked more on open vented systems and often the feed and expansion pipe will have a build up of scale/debri on the walls and in any elbows (should not have any should be cont rise),often easy to just change the pipe. Only ever managed to clean them out partially even with a mechanical cleaner atached direct. The bad news is that if the g/w is blocked then the plate will not be fare behind especially if any of the drains were blocked or the translucent plastic manifolds are black. Your not up north by any chance ?

 

[PEDANTICVINDICTIVEMAN]

No not up north, midlands, trans mans not black, I suspect pcb as pump doesnt run on after DHW draw off finished, if the heating is running no banging after draw off as pump is running and shoving heat into rads, pump runs on after heating is turned off though.
22mm feed/vent pipe is straight of boiler and only about 500mm to tank with one elbow and rises all the way, also fills up quickly when refilling.

 

[COG]

Pump overrun kicks in when temp at ch sensor is above 55c ,the noise is usually after the gas has shut down ,never had no pump overrun on a heatronic board , have had loss of power to the pump a few times (stalling) but that just comes with no warning in seconds.

 

[PEDANTICVINDICTIVEMAN]

80 Cel not 55 Cel