No hot water & water pressure drop in combi boiler syste

Hi,

I am currently leasing a flat and the letting agent just placed a Worchester Bosch Greenstar 24i junior combi boiler. I could not find the water tank in the flat, so I am assuming the tank is shared or its based on a direct water system.

There are a few problems I have encountered:
1. When I turn on one tap (either hot or cold) and turn the other tap, the water pressure of the taps drop. Its like the water pressure is cummulatively shared between hot and cold water.

2. When there is a sudden need of water like after flusing down the toilet or during washing clothes, I notice that there is no hot water at all when turning on the tap. Only cold water comes out. Once the the tank is full or after washing is done, hot water comes back.

I am currently using some sort of eco button with a timer so the water is only heated at specific times of the day. Says in the manual, no preheat water is available. but it does not matter as the timer fixes that problem. Since its summer, I don't need it turned on all the time. What I do notice is that even though I do the washing outside the timer period, the hot water temperature is not affected after that. So I am guessing there is sufficient hot water to last me the entire day. The system pressure guage is within normal water pressure.

Any ideas how to tackkle the problem? Thanks all for the help.

Welcome to the World of "Combi" Boilers, there is not much that can be done about the flow rate, as you are right, in that the water flow is combined between the hot & Cold sides, so the flow issue is one that you will have to learn to live with, the "Eco" function basically stops the boiler from "pre-heating" a small quantity of water within the boiler, as you have found even on the "Eco" setting and the timer "Off" you will still get Hot Water, this is normal as combi's are designed to give on demand hot water around the clock hope this is helpfull

Hi,

Thanks you for the info I am stuck with this then. I'll manage the water better from now on.

Since its summer, I don't need it turned on all the time.

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There seems to be some confusion over what this "preheat" is doing for you. A combi boiler supplies you with hot water, any time you want it, as soon as you want it. OK, maybe 20-30 seconds after you turn on the hot tap. All the preheat function does is to keep things warm inside the boiler so you get the hot water more rapidly when you turn on the tap. The preheat is not storing any hot water. The temperature of the water supplied will be the same with or without it. You can run the hot tap all day long and it will always be hot, again with or without preheat.

Sounds like your cold water pressure is very low. Either that or the installation is faulty! What did you have before this boiler? The cold water in a flat might come from a tank or in smaller properties it may be forced up from the mains at street level. Either way the pressure can be much lower than most people would expect in a house. Combi boilers need a minimum water pressure to operate properly, so this boiler might not have been the right choice for you.

ianniann said:

Since its summer, I don't need it turned on all the time.

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Sounds like your cold water pressure is very low. Either that or the installation is faulty! What did you have before this boiler? The cold water in a flat might come from a tank or in smaller properties it may be forced up from the mains at street level. Either way the pressure can be much lower than most people would expect in a house. Combi boilers need a minimum water pressure to operate properly, so this boiler might not have been the right choice for you.

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My flat is on the second floor of a 3 floor flat. There is sufficient water pressure when I turn on the tap, but its not to the point of the water splashing everywhere once the tap is fully open just the volume is as high as it can get.

I have check the pressure, it is above the minimum by quite some margin.

Before this I did not have any boiler I just moved into this flat and the letting agent said they were replacing the 15 year old boiler (which you need to press a starte button a lot of time and look into the glass to see the pilot flame). That boiler did not even work. I got a new boiler after a week in the new flat.

Is there a way for me to increase the preassure myself without calling people from the letting agent?