ALPHA OCEAN 240X - DIFFERNTIAL PRESSURE ASSEMBLY

[taxidriver]

Hi,
My mum has just moved house, and her DHWater only heats up if the tap is turned full on (flow rate 7.5 litres/min). I've already replaced the diverter diaphragm, but that made little or no difference and the old one looked OK any way. I removed the differential pressure assembly to check the filter, and found the venturi part on the end was missing altogether.

I found the little coil spring when I removed the cold water inlet filter, but there was no sign of the rest of it. I have been trying to find a replacement part on-line (i.e. the whole assembly or just the venturi bit which screws in the end). UK-plumbing stock the hydraulic venturi assembly for the Baxi 105HE (part 248051), which I understand from other posts is basically the same boiler. Is anyone able to advise whether these parts are interchangeable, or if not, where I can get the pukka part for the Alpha please?

 

[Agile]

I have encountered that problem once or twice and some of the parts had apparently disappeared out of sight.

I was able to make a temporary solution with a washer to restrict the flow and when I go there next I will replace the whole assembly. That was nearly 9 months ago now.

I would expect the Baxi part is the same but it might not be. You should be able to get a parts merchant to order the correct one for you but its probably worth taking the risk of trying the baxi part if its in stock. Note there are two different colour plastic inserts and you really need the one for the 24 kW rather than the 30 kW.

Tony

 

[taxidriver]

Tony,
Thanks for the quick reply. The plastic restrictor is still there as its held in by the brass 'screw' part. It's the bit on the end of that which is broken off (it has four thin bits of brass connecting it to the main body). I only know it should be there from the exploded view in the installation manual as the breaks aren't clean any more, so it must have been like that for a good while.

The part for the Baxi is only a tenner, so it's worth the risk if it's likely to fit. Looks the same on the exploded diagrams for the 105HE and 240X, just thought I'd check on here first. The problem is I can't find a full parts list for the Alpha, so it's difficult to know whether you've found the right part or not just from the descriptions as most of the on-line suppliers don't give pictures or tell you which boiler the parts actually refers to.

Neil

 

[Agile]

Note there are two different colour plastic inserts and you really need the one for the 24 kW rather than the 30 kW.

The cage on the end is usually only made of plastic and contains a light spring and a plunger. The plunger lifts when the flow exceeds a few li/min and this creates a greater differential across the diverter at low flow rates.

The insert is a flow rate equaliser and has a black "O" ring which is pushed forward by higher pressures to lessen the flow.

Even if the caged part is missing the diverter still usually responds pretty well and it makes me wonder if that "O" ring is missing from yours.

Tony

 

[taxidriver]

Thanks again Agile Tony. I think the insert was blue (memory's not what it was). The missing cage might well have been plastic. The spring is there, but no sign of any plunger or 'O' ring. It takes three times the minimum flow in the manual (2.5 l/m) before the diaphragm plunger operated the microswitch, so hopefully a new part will sort it if it fits OK.

Neil

 

[gas4you]

Try Alpha part no. OCEAN 6.5630020 PRESSURE SENSOR

Parts center catalogue no. 450012

I think this is the complete differential assembly

 

[Agile]

The "O" ring is INSIDE the flow restrictor insert! Its pretty tiny perhaps 5-6 mm diameter and 0.75 dia.

They sometimes get blown out!

I often remove them completely if there is a serious flow problem.



Tony

 

[ChrisR]

This is Alpha240 dv,
and this is the other bit.

 

[Agile]

Yes, thats better, now everybody can see it.

I am surprised that baxi list every little bit.

Perhaps I should try ordering a little bit!

Tony

 

[ChrisR]

Would have shown the baxi bits but as you can see from the parts list it wouldn't help:
80 248050 E66418 Hydraulic Inlet Assembly 1
82 248051 E66419 Hydraulic Venturi Assembly - Not Shown 1
84 248052 E66421 Filter - DHW - Not Shown 1
85 248053 E66422 O-Ring - Venturi Assembly - Not Shown


Oh look a RUDE PERSON has ejaculated in the middle..

 

[taxidriver]

Thanks for all the replies, I've decided to risk it and try the Baxi part first as it is only £8.85 for the complete assembly (Incl VAT). The equivalent Part Centre price for the Alpha part is £52.67, although now I know the correct part number, I was able to find it for half that price.

I was surprised at the on-line prices at Parts Centre in general: £291 for a DHW heat exchanger, £254 for a diverter valve £37 for an O-ring! What's going on there?

Neil

 

[Agile]

Well tell us the result when its fitted!

There are prices and prices!

Bit like taxi fares I suppose !!!

 

[taxidriver]

Like there are rip-offs and RIP-OFFS I suppose!

The Baxi part turned out to be just the venturi bit (spring, cage, plunger etc.) so the price comparison wasn't actually like for like. However, that's all I really needed and it fitted the Alpha housing fine, so they are the same part. An O-ring from Focus (pkt of 6 for £1.30) later and job's a good'n. The boiler now fires up at just over 2 litres/min and the water's HOT!

Thanks again for your help.

By the way Gasbits.com stock the Alpha parts and are much cheaper than Parts Centre.