No hot water in the morning

asperity · 22 Feb 2015

I have a 3 year old Worcester 30 combi boiler, as well as a megaflow, closed system. There are 3 of us in the house.

Our heating and hot water is controlled by a Honeywell Timer which seems to be working correctly.

The hot water is currently set for 0530-0800 and then 1800-2100. It was set to come on at about 0600 but I moved it forward to try and solve the problem, which did not work!

Over the last couple weeks, the heating has been fine, but the hot water in the morning is only lukewarm for showers. Its warm enough from a tap though- its as if the hot water wont work in the shower (its not only one shower, so I know its not the thermostat). Weirdly, its fine in the evening for a bath.

Forgive me if I am being thick, but what am I doing wrong??

buck51 · 22 Feb 2015

Your post is lacking so much info, I guess that's why you have had no response so far.

Do you work 7 days a week? if not then why dont you time how long it takes to get up to the set temp, on your day off?

when did it last work ok?
What as changed?
what runs off the combi?
what runs of megaflow?
If you want help then you have to give us all the relevant info,

I would guess the last time it worked ok, was in the summer, or when the weather was much milder than it is now.

asperity · 23 Feb 2015

thanks

when did it last work ok? up until a couple weeks ago

What has changed? i dont know! it has gotten colder. the only thing that has happened of significance was that over the summer we had work done in one room which meant that they had to remove the radiator. That led to the system being drained down twice. Then. when we put the heating back on, the valve was not working, so it got drained down a third time. but the heating has been fine since.

what runs off the combi?
heating and hot water

what runs of megaflow? hot water definitely. I dont think its got anything to do with the heating, other than keeping the pressure up.

If you want help then you have to give us all the relevant info.

happy to answer all questions.

Madrab · 23 Feb 2015

OK, you have a sealed system (closed?) and a megaflow?

Is it a single 3 port valve system with a 2 port valve on the primary feed to the megaflow or 2 2 port valves?
Have you checked the cylinder thermostat is up at >60Deg?
When you have the boiler on hot water, do the valves activate properly and the feed and return pipes on the megaflow heat up?

asperity · 25 Feb 2015

okay, trying again with this problem. I've had a plumber round who told me there was nothing wrong, just leave the hot water on continuous and then there will be hot water in the morning. I did that and its not work. The good news is that it wasn't a complete waste of time as I understand more about how the system works.

So the condenser boiler only heats the megaflow cylinder, meaning that the heating runs off the boiler, not the hot water. The hot water comes from the megaflow. When I try and get hot water, it runs fine to the bath and the taps. The problem is hot water at pressure. While the outlet pipe does go hot, still, with either of the showers which require pressure, the water is only lukewarm. I fail to believe both the thermostats are on the blink at the same time.

As I said before, this problem has only happened in the last two weeks.

Any ideas? I'm loathe to get another plumber in until I understand a bit more.

ScottishGasMan · 25 Feb 2015

To be honest, it does sound like the showers or the installation is at fault.

If you can run a hot bath in the morning, the cylinder and boiler are fine (End Of)

Either your showers are knackered (mixer showers are notorious for such problems)

OR

there not being fed from a balanced supply.

A balanced supply: The hot water in the cylinder is controled at pressure via a pressure limiting valve, the cold main is not. The cold to mixed supplys such as showers should be fed from the limiting valve to ensure the cold feed doesnt have more "force" into the mixer than the hot.

If you can get a few pics of the cylinder, especially the limiting valve (brass valve between 2 and 4 connections with a plastic bit sticking out it on the cold feed to the cylinder normaly in compartment next to it

TeaTime · 25 Feb 2015

I would agree with SGM that since this seems like an issue with the shower, I would assume you have a thermostatic mixer shower. Try replacing the thermostatic cartridge / fitting a pressure reducing valve on the cold inlet to the shower.

asperity · 25 Feb 2015

Okay pictures uploaded. I can send more if you need.

//www.diynot.com/network/asperity/albums/

I would understand if it was one shower but for both to fail seems a bit too coincidental.

TeaTime · 25 Feb 2015

If you are getting hot water from other outlets but not through the showers, I would be looking at the showers.

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No hot water in the morning

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