EcoTEC VCW 296 Pump replacement question

[StClaus]

Hi everyone,

I've been browsing the interwebs on this matter a bit, but this forum is the only one that gives any answers, so here goes.

When we bought our house (in Flanders, Belgium) it came equiped with a Vaillant Combi Condensation Boiler. I've never found any paperwork on it anywhere, but using the Serial Number i've identified it as a VCW BE 296/3-5H. VCW 296 for short. I would estimate the age at about 7 - 9 years.
I've had to top up the pressure every now and then, but I thought this was normal.
About half a year ago there was a rumbling noise when the Central Heating switched on (= the pump rumbled when it had to pump around the house).
And this winter it happened quite a few times that we woke up to an icecold house and a boiler that somehow lost it's pressure overnight and decided to render an error-message rather than some heat.

A few days ago this started happening non-stop (could not keep pressure AT ALL) and water was leaking out of the housing of the boiler. Red alert.
I opened up the housing and found the leak to be on the underside of the pump (between the metal motorhousing and the plastic housing).
I've taken out the motorhousing of the pump and found that in the thin aluminium casing that surrounds the impeller shaft and is supposed to keep the watery bits seperate from the electrical bits there is a pinhole. And there is definitely water, rust and other muck in the electrical part of the motor. Also the shaft/impeller is a bit wobbly in my opinion (as in : it's in there loosely but not nice and snug like inside a bearing).

Sooo... pump broken, has to be replaced. I've tried to get hold of a plumber(s), but they either don't show up, or they give me the inmpression they know nothing more about it than me.
Sooo... I'm gonna have a go at it myself.
(see next post for rest of story)

 

[StClaus]

(Part 2)

The pump is a Wilo (Silver label with black lettering)2-speed pump VPAR-5 with art. nr. 0020005803.
I'm in the understanding that these are no longer used, but now Vaillant uses Grundfos pumps (Black label with white lettering)

Q1 : Can anyone give me confirmation that the correct replacement pump would be the one with art. nr. 178983 ?

I've found this pump for sale online, but it's advertised with a picture that shows a Silver label with black letters. So this leaves me to think that somehow that would be a Wilo pump again. Which is better than no pump at all, and with the added benefit that I probably can just replace the motor housing without having to hassle with the piping and connections.

But - and this is what I would need to know before I order it - in the event that the picture is that of a Wilo pump, but in fact they ship the Grundfos, I'll have to replace the pump completely.
I've seen and read that the Grundfos Pumps turn counterclockwise.

Q2 : Is it normal that the replacement pump would turn in the other direction?
Will this work or will it destroy other parts of the boiler?


Thanks for reading my looong post, and any replies are welcome.
The quicker the better, since we are stuck in an unheated house with no hot showers (damn combi boiler!)

 

[GuessMan]

178983 is the replacement for >31kW and 0020025042 for the bigger versions. Will are no longer used. Follow the instructions in the box.

 

[StClaus]

Thanks!

The Max warmwater-output is rated at 29kW.
So i guess that the 178983 would be the correct one then.
It has VPAL 5/2 on the label, which seems in accordance with the VPAR-5 on the broken pump.

The labels however are different. On the broken pump the silver label is a circle with flat sides (like on the 0020025042 pumps), but the 178983 has a complete circular label. You would expect it the other way round. Nice touch from Vaillant to add some confusion there ...

 

[StClaus]

The pump is replaced, but i've got another problem now. During the first test of the boiler the pipe for the overpressure valve on the pump blew off giving me a lukewarm shower. Unfortunately it also tripped the main differential.
I cut the waterflow and immediately started blowdrying the PCB. But everytime I start up the boiler I get error F.67 . Is it because I overheated the electronics while blowdrying (solved by letting it cool off I guess) , or are the electronics murdered by the voltage peak when the differential tripped ? The Vaillant Manual just says to change the electronics, but I'd line to know the real reason why...