Fixing leaky tap in indirect unvented system

[jonlarge]

Hi,

This is my first post so hello everyone.

I need to fix a leaking hot tap downstairs and we have an indirect unvented system (well we have no tanks in the loft, and a Megaflo in the airing cupboard).

I've been reading up this evening on how the system works and, indeed, the system's correct nomenclature.

To fix the tap I need to drain the hot water and I'm not exactly sure on what I'm going to do so I thought I would run it past this forum first. Here's my plan:

1. Switch off heat source (boiler in kitchen)
2. Switch off the cold water supply to the Megaflo (there's a lever on the pipe feeding into the base of the tank rather than a red-tapped type valve)
3. Open the cold taps (not in the mains fed kitchen) to drain the storage cistern/tank.
4. Once the cold taps have run dry open the hot taps to drain pipes and partially drain the hot water cylinder
5. Repair tap
6. Close all open taps
7. Resupply cold water to cistern/tank

How does this all sound? I've read that I can drain the tank from a drain valve (and hose) at the cold water inlet, but using the taps sounds more practical!

Thanks in advance for any help you can offer me.

Jon

 

[swidders]

I may be wrong here, but don't you just turn the boiler off, turn the cold supply to the megaflo off, and turn hot tap on to drain pressurised hot water off until it stops after a few seconds?

 

[Aquaheat]

1. Switch off heat source (boiler in kitchen)
2. Switch off the cold water supply to the Megaflo (there's a lever on the pipe feeding into the base of the tank rather than a red-tapped type valve)
3. Open the cold taps (not in the mains fed kitchen) to drain the storage cistern/tank.
4. Once the cold taps have run dry open the hot taps to drain pipes and partially drain the hot water cylinder
5. Repair tap
6. Close all open taps
7. Resupply cold water to cistern/tank

1. yes
2. yes
3. no need as you have already said you don't have any plus the hot and cold are seperate supplies.
4.just open the hot tap and you will find it will stop after doing "2"
5. yes
6. yes but i would always leave one hot tap slightly open to prevent airlocks then turn off when you get full pressure
7. again no need as you say you haven't got one.

Not 100% about 6 but i'm sure i'll be corrected, it's just the way i like to do it!!

 

[Gas2Air]

Turn mains water off, or if fitted valve on the cold supply to cylinder. Drain from HW tap(s), upstairs first. Beware when you correct fault and turn water back on, the tap(s) will have air in and will spit a tad

 

[jonlarge]

Just wanted to thank everyone for their replies.

As usual with these sort of projects it's the bits you don't think about that turn out to prevent you from easily completing the job!

Turning the water off was the easy bit. Turned water heating off, shut cold water feed to MegaFlo, turned on downstairs tap that I was repairing, and about a teacup of water came out and that was it. All ready for the repair...

Took the head off the tap, but couldn't release the headgear. Several doses of WD40 and some waiting time later I ended up removing the tap from the basin to allow me better access...inevitably I ended up rounding the nut off.

Off to Wickes then and eventually, four hours after starting (allowing for lunch of course), I have replaced two taps. I hope my re-tightening stays OK.

The cold tap was isolated just by turning off the mains feed under the kitchen sink. When it came to turning on the cold feed to the MegaFlo I got the other half to stand by the hot tap downstairs checking it wasn't spitting out everywhere. At time of writing the boiler's on and a bath has been run...and I have a working, spare cold tap should I need one!

Cheers again everyone! For the desperately sad I have blogged my story, complete with photos...