Poor Hot Water Flow.

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Hi,

Just moved into a flat a few week back and the hot water flow is really bad. Nothing wrong with the heat as water is good and hot. Its just that the amount of water coming out is pretty bad. Takes nearly a minute to fill the basin to wash my face in the morning (and its not a monster basin or anything). I don't use bath, thank god. Electric shower so that is fine.

Its a small 1 bed flat. There is the kitchen sink, bathroom basin and bath. Kitchen pipe run is 1-2m. Bathroom pipe run is 3-4m. I know that I do not need to use all three taps at the same time but flow is so poor that if you have the kitchen tap running full pelt and turn bathroom basin tap on, kitchen one completely stops. Turn basin tap off again and kitchen starts up again. Basically, only one tap can run at any one time.

Heating is fine so boiler is working on that side of things.

Boiler is a vokera compact 28 if that helps. Don't know how old it is or if it was looked after (serviced) by previous owners. Looks quite old so def not a modern boiler.

I have read quite a few similar posts and looks like everything points to the boiler and a blocked heat exchanger thing. Live in Scotland so hard water probably doesn't come into the mix. What else could block it or will it be something else. Cold water flow is great. I have not measured the flow of each though. Cold tap could fill a pint glass in maybe a few seconds, hot would take maybe 15 secs or so.

I have also already checked that any and all valves are open as I have read this on a number of posts also.

Looking to call out an expert but would like some additional information, so that I do not get lost if he starts talking technical. Does it sound like an easy & cost effective fix. The last thing I want is to replace one thing (heat exchanger) for it not to work, then get the next thing replaced and then something else and then all of a sudden I am several hundred quid down and no improvement if that money could be better spent being put towards a new modern boiler from the get go.

Thanks.
 
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Assuming the DHW flow valve under the boiler is fully open...

Then there's a flow limiter device in the rear cold water connection to the heat exchanger....pulling out the O ring (that will be solid) normally sorts the problem.
 
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Gasguru.

Thanks for the quick reply.

Incoming cold water flow valve/stop cock is open. There is no valve on the hot water out side though. Just a compression elbow.

Flow limiter device - I assume this comes pre-fitted in the boiler and is some sort of washer thing with a narrower diameter hole which reduces the amount of water that can physically go through the boiler. I also assume that the removal of this device is a gas safe engineers job as it is inside the boiler. Is it designed to be removed (at installation stage) if water flow in a property is found to be low, like mine and that it just wasn't done at the time, either in error or just didn't bother.

I assume if I get a guy in, he will be be able to diagnose the same as yourself and do the work easy enough or should I tell him about your reply and just get him to remove the limiter from the get go.

I assume the boiler still functions ok without this limiter and you just get a better flow rate or will I have to sacrifice some heat/temp for a greater flow/pressure. Like an electric shower but in reverse, where when you turn up the heat, flow reduce but with the boiler, when flow goes up, temp come down.

I appreciate the reply.
 
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You can access the flow limiter without removing the inner combustion chamber cover. It sits in the screwed pipe connection to the heat exchanger at the back on the RHS. The O ring starts life pliable restricting the water flow, as the O ring hardens and becomes contaminated it begins to restrict flow. Just remove the ring. It's worth checking this before assuming the hex is scaled up. Get yourself a 1/2 fibre washer beforehand.
 
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