Boilermate 2000. No hot water.

I am still waiting for someone to give me an explanation why anyone would fit one of these in preference to an unvented.

Stored mains pressure water is less than 15litres which means there is less risk of an explosion so you don't need an unvented ticket.
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To get on to the question. Quite a common thing is that on the ACB the light comes on indicating that power is going to a pump but the voltage is not full 230v.
Once it gets less than about 170v the affected pump slows or fails to work completely.
This is due to an often heat sensitive fault on the octocoupler chip immediately to the right of the relevant light.
Basically these things are the modern equivalent of a relay.

Sometimes the situation will improve if you leave the cover off.

When the pump light is on applying heat with a hair dryer and then cooling the chip down with an air duster has proved a faulty octocoupler by checking the output voltage.

Quite often there is a spare chip at the top that you can see on page 22 of these instructions which could possibly be moved down to the location of the faulty one or as I got away with once rerouting the wire on the board so that this spare chip was used and simply followed the track to pick up a new switched live location

It cost me about £35 to get 10 of these chips from China through ebay but I would probably need a 'heat station' to remove and replace one. Better than a soldering iron these spread a flow of very hot air across the area at the back of the chip allowing the full chip to be removed in one piece. One day when I'm not so busy I will get all my old boards together and give them to a mate who can sort a few out for me.

When going through the sensor test sequence and you get to the 'H' give the wire a wiggle near the sensor to see if the 'er appears after it. [Hºer] Sometimes this denotes an intermittent fault.
Tony wrote
I am still waiting for someone to give me an explanation why anyone would fit one of these in preference to an unvented.

Simply because this is a HEAT store and is used to supply hot water and heating. Unvented will supply hot water only.

Furthermore, mains cold water is heated in the coil on demand* when needed as opposed to being stored hot water as is in an unvented cylinder.

* I use combi HW to fill the kettle for quicker brew, but would be reluctant to used HW from tap supplied by a UV cylinder. For Boilermate 2000 read Combi boiler:cool:
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Slug you can get a desoldering pump from Maplins. If you were in Glasgow, I could desolder the chips as have desoldering station too:cool:

What is the chip designation?

Tony an optocoupler need not be in form of a chip. It can comprise a light source and a detector with light providing the coupling hence the designation- optocoupler.

Further, a chip can have 4 legs, 6 legs, 8 even as shown in the manual. Larger configurations are available where the packaging can have there, four, or even more opts in the single package

It is highly likely the optocoupler fitted on the 2000 could be a darlington device in the package with pins 1 and 4 not connected ;)
These ICs are opto coupled triacs !

They are used to drive the pumps in that application.

Most often in a six pin package though.

Tony either I need to visit Specsavers or I am seeing 8 pin packages in the drawing. Can you back up your reply with a chip number e.g. NE555 which is a timer :LOL:

HCPL-090J-000E trans opto isolator, SO16- is a 16 pin package

Have Googled but have not seen an eight pin optotriac :confused:
Here you go mate,
I got a pack of 12 from through ebay There's no price on the delivery slip but as I said I'm sure I paid about £35 for them

Part number S26MD02
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