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Hi All!
My first post here.. I need some help from someone who really understands central heating systems, pipes and radiators.
New boiler installed
My 20 year old Ideal Mini boiler finally failed in December with no hot water and it was leaking all over the floor. It turned out it would be much quicker to get someone to replace my boiler that get someone out to repair, so that's what I did. I had had something like 15 callouts over the past 10 years with constant issues so I decided to go for a new boiler. I ended up with a 26kw Viessmann Vitodens 100-w with a Vitotrol 100-E load balancing controller both of which I've been very pleased with so far.
Radiator problems
I have had some issues with my radiators. These issues were not caused by the boiler installer, but something I noticed after the install. They are not heating up properly and have cold spots along the bottom. I'm making this post because I need your help to figure out what to do with my radiators and pipes, whether I should just get a more aggressive flush, replace all the radiators, and potentially replace two 10mm microbore pipe runs to the living room and kitchen radiators. These two runs are approximately 6 meters each (feed + return together) from a 15mm feed.
Flush was mostly skipped
The installers were supposed to perform a full Magnacleanse flush, however I think they just put the machine on for at most 40 minutes and then disconnected it, skipping most of the steps. I understand that they are supposed to:
1. Add cleaning chemicals
2. turn all radiators off and focus on one radiator at a time
3. Agitate each radiator with an SDS drill with a soft attachment to dislodge sludge
4. Once complete, drain the system and re-fill with inhibitor.
I was in the house all day while it was installed, and none of those 4 steps above was carried out, which I'm quite disappointed with. My radiators all seem to have cold spots. I was told that it's hard to flush 10mm microbore pipes, and that sometimes it's more trouble than it's worth, but 15mm is fine. As seen below, my downstairs radiators on 10mm pipes and this could be a problem.
Radiator/pipe setup
The house is a small 2 bedroom semi with 4 radiators and a towel rail. The house originally had electric heating but the boiler and pipes were retro fitted in 2004, so the system is 20 years old. The boiler is in the loft and feeds the house via 22mm copper pipes. These pipes then go under the floor upstairs and feed the downstairs radiators with 10mm microbore pipe and the upstairs ones (and towel rail) via 15mm pipe. The microbore pipes don't have any manifold, just copper joints from 15mm to 10mm right before they go downstairs. The total length of the 10mm sections for each downstairs radiator are about 6 meters per radiator. The downstairs radiators do get flow and get hot, but they do seem blocked at the bottom. When I purchased the property in 2014, there was no filter attached to the system and the water was disgusting. A power flush was done in 2015 and a magnetic filter was fitted at the same time. This kept the water quality good until now, however there was 11 years with no filter at the beginning of the system's life which could have filled the radiators with sludge.
I also have discovered my towel rail does not have a locksheild valve. I need to get this replaced, for now I have towel rail set very low (1.5).
I have the following radiators:
Thermal testing
I decided to conduct a proper test to see how the radiators heated up with a thermal camera.
Outside weather: -1C to 2C
Inside temp: set to 16C through the night until 6am
Heating turned on at 6am, thermostat set to 20C
Boiler flow temp setting: 70C
So I turned the heating on at 6am, and took 6 thermal pictures of each radiator over the course of 1 hour 18 minutes. I placed a few measurement points/lines on the images to get an idea of the cold spot and hot spot temps. Please see all the pictures at the bottom of this post. I'm also going to summarise the temps in a table.
I have not included the towel rail because it always gets evenly hot, and because it's silver and reflective, I couldn't get a good measurement with the IR camera.
Temps below are in degrees C. hot and cold temperature readings below are the hottest and coldest spot measurements from each radiator. Please also see the infrared images at the bottom of this post - all these numbers were taken from those images.
The bedroom radiators began to shut off towards the end because the TRVs closed the valves. They are set low because that's all that's needed to keep upstairs warm.
Please help!
I would really like someone to look at the setup, the table above and the thermal images below and tell me whether I should:
1. Replace all my radiators
2. Replace all my radiators AND the 10mm microbore pipes feeding Living Room and Kitchen
3. Replace just the worst radiators
3. Get the company back to do a proper flush and see if it helps
4. Leave the current setup as-is
Also:
A. Can microbore 10mm be flushed successfully?
B. Are my radiators blocked? or not too bad? Are they heating up as expected?
C. Is it worth replacing the 10mm microbore?
D. Can 6 meters of 10mm microbore really feed a 600x1200 Type 22 radiator properly?
E. My existing system as 3x rads on 15mm and 2x rads on 10mm. Isn't this asking for trouble? I know locksheild/balancing can help.
F. Is my system out of balance? Should it be re-balanced?
Thermal images - 6 measurements over 1 hour 18 mins. Feed/Return in the images is the 22mm feed from/to the boiler before any radiators.
06:01 - Heating just turned on
06:05 - running for 5 minutes. All radiators seem to be blocked at the bottom
06:13 - All struggling to heat the bottom still, Bedroom 2 is doing ok. It's the closest rad to the boiler.
06:21 - Living room 13C difference between cold and hot spot, Kitchen 9C difference, Bedroom 1 14C difference, Bedroom 2 10C difference.
06:45 - Bedroom 1 TRV has restricted flow so this rad is cooling down. Bedroom 2 starting to shut off. Living room and kitchen still struggling at bottom. Living room - 12C difference between feed and cold spot. Kitchen, 8C difference between feed and cold spot.
07:18 - 1 hour and 18 mins into heating turning on. Bedrooms shut off mostly, so blockage not visible. Living room really struggling at bottom with 11C difference between inlet and bottom. Kitchen has evened out a bit but bottom still looks a little blocked, 8C difference between cold spot and hot.
My first post here.. I need some help from someone who really understands central heating systems, pipes and radiators.
New boiler installed
My 20 year old Ideal Mini boiler finally failed in December with no hot water and it was leaking all over the floor. It turned out it would be much quicker to get someone to replace my boiler that get someone out to repair, so that's what I did. I had had something like 15 callouts over the past 10 years with constant issues so I decided to go for a new boiler. I ended up with a 26kw Viessmann Vitodens 100-w with a Vitotrol 100-E load balancing controller both of which I've been very pleased with so far.
Radiator problems
I have had some issues with my radiators. These issues were not caused by the boiler installer, but something I noticed after the install. They are not heating up properly and have cold spots along the bottom. I'm making this post because I need your help to figure out what to do with my radiators and pipes, whether I should just get a more aggressive flush, replace all the radiators, and potentially replace two 10mm microbore pipe runs to the living room and kitchen radiators. These two runs are approximately 6 meters each (feed + return together) from a 15mm feed.
Flush was mostly skipped
The installers were supposed to perform a full Magnacleanse flush, however I think they just put the machine on for at most 40 minutes and then disconnected it, skipping most of the steps. I understand that they are supposed to:
1. Add cleaning chemicals
2. turn all radiators off and focus on one radiator at a time
3. Agitate each radiator with an SDS drill with a soft attachment to dislodge sludge
4. Once complete, drain the system and re-fill with inhibitor.
I was in the house all day while it was installed, and none of those 4 steps above was carried out, which I'm quite disappointed with. My radiators all seem to have cold spots. I was told that it's hard to flush 10mm microbore pipes, and that sometimes it's more trouble than it's worth, but 15mm is fine. As seen below, my downstairs radiators on 10mm pipes and this could be a problem.
Radiator/pipe setup
The house is a small 2 bedroom semi with 4 radiators and a towel rail. The house originally had electric heating but the boiler and pipes were retro fitted in 2004, so the system is 20 years old. The boiler is in the loft and feeds the house via 22mm copper pipes. These pipes then go under the floor upstairs and feed the downstairs radiators with 10mm microbore pipe and the upstairs ones (and towel rail) via 15mm pipe. The microbore pipes don't have any manifold, just copper joints from 15mm to 10mm right before they go downstairs. The total length of the 10mm sections for each downstairs radiator are about 6 meters per radiator. The downstairs radiators do get flow and get hot, but they do seem blocked at the bottom. When I purchased the property in 2014, there was no filter attached to the system and the water was disgusting. A power flush was done in 2015 and a magnetic filter was fitted at the same time. This kept the water quality good until now, however there was 11 years with no filter at the beginning of the system's life which could have filled the radiators with sludge.
I also have discovered my towel rail does not have a locksheild valve. I need to get this replaced, for now I have towel rail set very low (1.5).
I have the following radiators:
| Location | Size (mm) | Type | TRV setting | Pipe size |
| Bedroom 1 | 600h x 700w | Stelrad type 21 | 2.0 | 15mm |
| Bedroom 2 | 600h x 700w | Stelrad type 21 | 2.5 | 15mm |
| Living room (Thermostat in this room) | 600h x 1200w | Stelrad type 22 | 5 | 6 meters of 10mm, rest either 15mm or 22mm. |
| Kitchen | 600h x 600w | Stelrad type 22 | 5 | 6 meters of 10mm, rest either 15mm or 22mm. |
| Bathroom | 1800h x 40w tall and narrow | Towel rail | 1.5 | 15mm, T junction with Kitchen 15mm feed. Missing locksheild valve |
Thermal testing
I decided to conduct a proper test to see how the radiators heated up with a thermal camera.
Outside weather: -1C to 2C
Inside temp: set to 16C through the night until 6am
Heating turned on at 6am, thermostat set to 20C
Boiler flow temp setting: 70C
So I turned the heating on at 6am, and took 6 thermal pictures of each radiator over the course of 1 hour 18 minutes. I placed a few measurement points/lines on the images to get an idea of the cold spot and hot spot temps. Please see all the pictures at the bottom of this post. I'm also going to summarise the temps in a table.
I have not included the towel rail because it always gets evenly hot, and because it's silver and reflective, I couldn't get a good measurement with the IR camera.
Temps below are in degrees C. hot and cold temperature readings below are the hottest and coldest spot measurements from each radiator. Please also see the infrared images at the bottom of this post - all these numbers were taken from those images.
| Time | Feed temp | Return temp | Bed 1 hot | Bed 1 cold | Bed 2 hot | Bed 2 cold | Kitchen hot | Kitchen cold | Living hot | Living cold |
| 06:01 | 50.4 | 26.1 | 41.0 | 24.2 | 48.2 | 28.9 | 38.9 | 21.2 | 37.9 | 18.6 |
| 06:05 | 70.0 | 43.3 | 54.6 | 27.9 | 60.1 | 38.7 | 60.0 | 38.9 | 56.4 | 23.1 |
| 06:13 | 70.1 | 57.0 | 66.8 | 50.9 | 71.5 | 58.9 | 70.2 | 59.3 | 66.2 | 50.9 |
| 06:21 | 72.2 | 62.6 | 64.6 | 50.6 | 71.5 | 61.0 | 71.5 | 62.4 | 68.2 | 55.1 |
| 06:45 | 70.5 | 61.0 | 42.9 | 30.3 | 64.0 | 55.0 | 69.3 | 61.5 | 67.4 | 55.9 |
| 07:18 | 71.0 | 60.9 | 36.0 | 24.3 | 40.9 | 33.4 | 69.7 | 61.5 | 68.4 | 57.4 |
The bedroom radiators began to shut off towards the end because the TRVs closed the valves. They are set low because that's all that's needed to keep upstairs warm.
Please help!
I would really like someone to look at the setup, the table above and the thermal images below and tell me whether I should:
1. Replace all my radiators
2. Replace all my radiators AND the 10mm microbore pipes feeding Living Room and Kitchen
3. Replace just the worst radiators
3. Get the company back to do a proper flush and see if it helps
4. Leave the current setup as-is
Also:
A. Can microbore 10mm be flushed successfully?
B. Are my radiators blocked? or not too bad? Are they heating up as expected?
C. Is it worth replacing the 10mm microbore?
D. Can 6 meters of 10mm microbore really feed a 600x1200 Type 22 radiator properly?
E. My existing system as 3x rads on 15mm and 2x rads on 10mm. Isn't this asking for trouble? I know locksheild/balancing can help.
F. Is my system out of balance? Should it be re-balanced?
Thermal images - 6 measurements over 1 hour 18 mins. Feed/Return in the images is the 22mm feed from/to the boiler before any radiators.
06:01 - Heating just turned on
06:05 - running for 5 minutes. All radiators seem to be blocked at the bottom
06:13 - All struggling to heat the bottom still, Bedroom 2 is doing ok. It's the closest rad to the boiler.
06:21 - Living room 13C difference between cold and hot spot, Kitchen 9C difference, Bedroom 1 14C difference, Bedroom 2 10C difference.
06:45 - Bedroom 1 TRV has restricted flow so this rad is cooling down. Bedroom 2 starting to shut off. Living room and kitchen still struggling at bottom. Living room - 12C difference between feed and cold spot. Kitchen, 8C difference between feed and cold spot.
07:18 - 1 hour and 18 mins into heating turning on. Bedrooms shut off mostly, so blockage not visible. Living room really struggling at bottom with 11C difference between inlet and bottom. Kitchen has evened out a bit but bottom still looks a little blocked, 8C difference between cold spot and hot.