Vaillant Combi DHW Flow Rate Nowhere Near What It Was.

[bigbaldbloke]

Hi all.

Complete & utter technophobe here, looking for advice on my domestic hot water before calling in an expert.

I've got a Vaillant VCW 221 H CombiCompact on a 1 pipe heating system. It's probably 20 years old....... I'm looking to replace both boiler & pipework in the Summer, but in the meantime our DHW flowrate has dropped to (at most) half of what it was a couple of months back.

We bought the house a year ago today & found gold-like flakes in the hot water, which I'm guessing might be the DHW heat exchanger on its way out. This has now stopped, at about the same time as the flowrate dropped, so I'm guessing that the heat exchanger has crumbled away & flakes are now blocking the smooth passage of hot water.

As I said, I'm a total technophobe, so for all I know, it could be something entirely different. I've also got my heating cutting out at around 15 degrees, although I'm not convinced that they're one & the same problem. I've looked through many posts here & have been impressed with the level of knowledge, so HELP! Please let me know what I'm probably going to be facing, and any recommended engineers in the Herts/North London area (I'm in Welwyn Garden City).

In the year that we've been here, we've had to replace the pressure release valve, filling loop & hot water tap washers (including tap reseating).

Many thanks in advance.

bbb

 

[mickyg]

Hi

Could be one of 2 things, there is a filter in the water valve which could be clogged up if foreign matter has come into your water supply from the mains(gold flakes??), or you could be right about the secondary heat exchanger. Unfortunately they get scaled quite easily in this area.
If you need an engineer you can email me, I'm going over to harpenden to look at a car in the next couple of days, can probably poke my head in on the way if necessary.
micky

 

[bigbaldbloke]

Cheers for the quick response Micky, you have mail.

 

[HARALIAN]

The golden flakes that you have in your sysem are the new breakfast cereal from kellogs ... I think theyre called Credit Crunch or something......Apparently we have all got a box in our cupboards!!!!

 

[bigbaldbloke]

 

[DP]

Why anyone would want to retire this workhorse I will never know. Keep it for goodness sake. Wheels on your pushbike would probably drop off before this boiler packs up. You do need an enthusiast to look after it though, not your "mister-your-boiler-is-too-old- you-need-a-new-one" type.

 

[bengasman]

Just keep it and find a good engineer to maintain it.
there is another possibility, water supplier may have turned pressure down to reduce leakage, thames water is infamous for that trick.
i have seen incoming mains work on less than 1 bar, and once on just over 0.5

replacing the boiler will cost you a pretty penny as i doubt if there is a way to get a 1 pipe system to comply with the regs of today

 

[mickyg]

Just keep it and find a good engineer to maintain it.
quote]

agreed

Why anyone would want to retire this workhorse I will never know. Keep it for goodness sake. Wheels on your pushbike would probably drop off before this boiler packs up. You do need an enthusiast to look after it though, not your "mister-your-boiler-is-too-old- you-need-a-new-one" type.

agreed

 

[mickyg]

you have mail.

it must be snail mail, not arrived yet

 

[bigbaldbloke]

Thanks for that Gents - I'd read on here that it's known as a long lasting beast & believe me, I'd rather not replace it (especially as the flue's above our conservatory). Perhaps Micky will fall in love with its olde worlde charm & become its guardian!

As for pressure, it's held nice & steady at 1.2 bar - although I raised it to 1.5 the other day in the hope of an increased flowrate.

 

[bigbaldbloke]

it must be snail mail, not arrived yet

Hmm, weird. Is the email in your profile the one to send it to Micky?

 

[mickyg]

yes thats the one, must be hotmail being its usual reliable self