My rads don't produce enough heat at 55c, but the engineers advised that the rads do not need replacing.
Interesting..
Is boiler underspec?
- Thread starter bruba
- Start date
Interesting..
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Agreed the heat link should be located where it is likely to get a good strong WiFi signal.
Also sounds like there is something wrong with the settings with the nest. Maybe switching to the hive may be better for them if they are more used to it, as long as they don't charge you for the pleasure of them doing so
Yeah they dont need replacing the boiler just needs to be set correctly.
If you wished for the heating to be a low temp heating system then you would replace the rads, but I just wanted a new boiler.
Unfortunately sounds like it's been done by monkeys who can sling a boiler on a wall but don't know how they operate.
Question- if a boiler is rated as (for instance) 18kw, is that rating at a specified water output temperature? If the rating is at a specified output temperature, what happens when you reduce that output temperature? Does the boiler increase the flow rate so the same energy per hour is moved around the house or does the flow rate stay constant so energy output reduces.
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Boiler outputs are often specified with two different flow/return temperatures, the lower ones because the boiler is more efficient as it condenses more might mean a increase of 1 to 1.5kw for a 18kw boiler but it is the heat emitters that determines its output up to its max rating. Rads are rated on a 50 deg basis which is the mean rad temperature minus the required rooms temperature, generally taken as 20C, a rad with flow/return temps of 75C/65C will have a mean temp of 70C, 70C minus 20C is 50C so a 50 deg rad or 100% rated output, a rad with 55/45C flow/return will only emit 51% of its rated output. (30/50)^1.3.
The easiest way to see if the boiler is underspecked is to take the gas meter readings over say 3 minutes or so, the boiler output can then be calculated.
The easiest way to see if the boiler is underspecked is to take the gas meter readings over say 3 minutes or so, the boiler output can then be calculated.
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Your rads may not provide enough heat at flow 55°C when the weather is at it's worth but if sized correctly will at a flow of 75°.
Whenever the weather is warmer however (the vast majority of the heating season) they will be adequate at the lower flow temperatures therefore chose a control system that aligns flow temperature with prevailing conditions and will increase or reduce flow temperatures accordingly.
I think based on above I will ask engineers to increase boiler output to 65C or thereabouts. When I told them that before they advised me that that would not be efficient! They don't seem to want to listen to me.
I am also wondering if the HeatLink is too close to the boiler. It is located right next to it and been advised it should be at least 30cms away. They should relocate it anyway as I cannot climbs the loft should I need access to the HeatLink for a reset etc.
Replacing the Nest with a Hive will probably not solve the problem unless the Nest is faulty which I very much doubt.
This will be the seventh visit, getting a bit tired of this now.
I am also wondering if the HeatLink is too close to the boiler. It is located right next to it and been advised it should be at least 30cms away. They should relocate it anyway as I cannot climbs the loft should I need access to the HeatLink for a reset etc.
Replacing the Nest with a Hive will probably not solve the problem unless the Nest is faulty which I very much doubt.
This will be the seventh visit, getting a bit tired of this now.
I'm not surprised! Are you having to pay for these visits, or are they still covered by the original installation agreement?
It must be hugely frustrating if the engineers aren't listening to you. Do you have anyone who can help you? I know you can't access the boiler yourself, but turning up the temperature is such an easy thing to do if you have someone who could help you. That seems the most obvious thing to try, before changing the thermostat system. Turn it all the way up to 75 and see if it makes a big difference.
Yet another poster who asks a question, doesn’t like the answer, then somehow actually “knows” the answer!
I don’t full agre with Hacks point on efficiency, but it is a bit weird that you selected the most expeuquite, despite offering a smaller, probably undersized , boiler.
One can only conclude that the “Grant” element factored into the odd selection
Later in the thread, the OP explains that they had no choice in the matter, and the boiler was sized and specified as part of the grant assessment.
Most new thermostats use TPI or similar algorithm.
The study into the effectiveness of these thermostats showed they actually increased energy use. And it concluded that it was probably because most people didn't understand how they worked. In the past, if you set a mechanical thermostat to say 22C, it might cut the boiler off at 23C, and everyone was used to that. But with TPI it might cut off initially at 20.5C. And many people find this confusing, so they just turn the temperature up until the boiler comes on again.
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On the Bosch boilers you have to use the Bosch proprietary controls to use this feature.
I'm not aware of any opentherm adaptors for the Bosch boilers like there are with vaillant
Have you a link to that study please?
They exist apparently.
Worcester Bosch and OpenTherm
Worcester Bosch and OpenTherm Worcester Bosch OpenTherm has eluded us here at MyBoiler.com for a while. New information has surfaced showing that it is indeed possible to use OpenTherm with a range…
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