Struggling Morso with back boiler

[tstore]

Hi all

Thanks for all the comments. Since the last time I posted, I have checked the area behind back boiler inside the stove and it was reasonably clear, I did clean end of winter this year too. Been getting stove nice and hot with glowing coals, not being timid anymore. Its heating up much better but the rads are still lukewarm. they occasionally get a little hotter but don't remain that way for long. It has a header tank, has water in it, does not boil. There is a thermostat on the outlet of the back boiler which kicks the pumps in. I have this set quite high, think its about 60-70 degrees, the max setting appears to be 70. So essentially there is approx 134ft of 22mm copper pipework circulating water from the back boiler around the boat. This is mostly unlagged too. 

 

[MtB]

On 16/11/2017 at 20:12, tstore said:

Been getting stove nice and hot with glowing coals

 

Frankly, no you're not. Given this:

On 16/11/2017 at 20:12, tstore said:

It has a header tank, has water in it, does not boil.

 

Given the rads are not getting hot, the water would be boiling furiously if you were getting the stove hot.

UNLESS as I said earlier, there is no water in the radiators. Have you checked? How did you check?

[smileypete]

5 hours ago, Mike the Boilerman said:

 

Frankly, no you're not. Given this:

 

Given the rads are not getting hot, the water would be boiling furiously if you were getting the stove hot.

UNLESS as I said earlier, there is no water in the radiators. Have you checked? How did you check?

I guess the 22mm goes in a U shaped loop and the rads are across it.

I guess it was intended to thermosyphon but the pump was added as that didn't pan out (understandably!) So while the loop is pumped the end bit shunts much of the flow to the rads, kinda like a totally off balance pumped system, leading the rads to have very poor flow, being hot at the top and cold at the bottom. Compounded by the OP possibly being too frugal with the fuel.

System sounds like another of these DIY abominations, (hope the OP didn't install it, sorry for any hurt feelings if so... )

Edited November 17, 2017 by smileypete

[Slim]

As I read it you have 2 possible issues 1) The stove simply not producing enough heat (regardless of how you measure it). 2) The rads not heating.

Point 1.  Others have covered issues such as flue blockages.  You say you are using coal. Coal  or smokeless fuel?  How much in weight over a given period? Does the stove have the normal fire bricks or has someone put more in reducing the capacity. Is the fire able to 'draw'. How about using a smoke pellet to confirm this. From initial lighting my Morso will get a good fire burning within 15 minutes. Truly effective heating takes about an hour. The body of the stove is HOT long before this.

Point 2. Apart from the design what is the total area of your 3 rads? Also consider the output of the pipework (I think you said 124' of 22mm. I have 2 rads and a number of finrads on a 2 pipe system that can be split into 2 sections. The full circuit is pumped, If I run the rads only the circulation is gravity. Pipework is 28mm. Even with the stove glowing the rads only get pleasantly warm. Remember, the stove only has an output of 5Kw and I bet the manufacturers had it glowing to achieve that.

[bizzard]

Its surprising how lovely and warm it could be with just the length of the pipe loop, without the wretched rads.  How they used to be when boat central heating began.

[BWM]

12 hours ago, tstore said:

Hi all

Thanks for all the comments. Since the last time I posted, I have checked the area behind back boiler inside the stove and it was reasonably clear, I did clean end of winter this year too. Been getting stove nice and hot with glowing coals, not being timid anymore. Its heating up much better but the rads are still lukewarm. they occasionally get a little hotter but don't remain that way for long. It has a header tank, has water in it, does not boil. There is a thermostat on the outlet of the back boiler which kicks the pumps in. I have this set quite high, think its about 60-70 degrees, the max setting appears to be 70. So essentially there is approx 134ft of 22mm copper pipework circulating water from the back boiler around the boat. This is mostly unlagged too. 

 

Any chance you could put a picture on of one of the underperforming radiators to see how it is plumbed in? If it's not wrongly plumbed in, one other option could be a very high flow rate on the pump, moving the water too quickly past the boiler but that's a long shot. 

[MtB]

On 17/11/2017 at 06:54, smileypete said:

System sounds like another of these DIY abominations,

 

Lol I thought this too, but was too polite to say.

My money is actually on the system having no water in it. I've encountered this a few times over the decades and a boiler will send a surprising amount of heat along pipes full of air and even heating radiators a bit sometimes. Especially if an almost completely blocked cold fill pipe is delivering a drip of water every so often to create a but of steam. 

Unblocking the fill pipe and filling the system properly after being run empty sometimes reveals a cracked heat exchanger though. 

[nicknorman]

2 hours ago, Mike the Boilerman said:

 

Lol I thought this too, but was too polite to say.

My money is actually on the system having no water in it. I've encountered this a few times over the decades and a boiler will send a surprising amount of heat along pipes full of air and even heating radiators a bit sometimes. Especially if an almost completely blocked cold fill pipe is delivering a drip of water every so often to create a but of steam. 

Unblocking the fill pipe and filling the system properly after being run empty sometimes reveals a cracked heat exchanger though. 

Easy enough to find out - you’d just have to open a radiator bleed valve.

[MtB]

On 17/11/2017 at 11:57, nicknorman said:

Easy enough to find out - you’d just have to open a radiator bleed valve.

 

Yep. The OP seems reluctant to actually engage in any dialogue though. 

[smileypete]

On 11/14/2017 at 13:18, tstore said:

 Rads are on one loop which travels the entire circumference of the boat even though rads are only down the one same side.

It's that bit which really intrigues me...

On 11/13/2017 at 20:34, tstore said:

I thinks it's rated at 5kw. The rad are on a single loop. You can isolate the first radiator and the towel rail ones but the rear cabin one you cannot isolate.

If there's no lockshield valve on the rear cabin one I wonder if this makes for a very poorly balanced system.

On 11/14/2017 at 13:18, tstore said:

The rads even when roaring still struggle and never remain warm for long. Bottom half of first ones stays cold, towel rail hardly heats up, small rad in rear of boat is the only which gets reasonable hot. Rads are on one loop which travels the entire circumference of the boat even though rads are only down the one same side.

If the rear cabin rad is hot all over, and the return pipe near to the backboiler feels pretty warm, yet the other rads are only hot halfway down, again this points to very poor radiator balancing.

On 11/14/2017 at 07:22, Jen-in-Wellies said:

Is the back boiler circuit also passing through a calorifier? On mine it is and I find that from cold, most of the heat from the Squirrel is being used to heat up the cauliflower. Only once the water is warm do the rads heat up and the stove itself seem to significantly radiate heat. When at work I'll keep the stove banked up with the vents stopped down low to keep the water warm, otherwise the boat takes hours to heat up with a roaring fire.

This is why I reckon it's worth having a thermosypyon 'heat dump' radiator near or next to the stove, it gives the option of retaining all the stove heat in the saloon. Some stoves backboilers take half the stove heat, like the Morso does, if the rads are all at the other end of the boat then that's where all the backboiler heat has to go (or to the calorifier).

8 hours ago, Mike the Boilerman said:

 

Lol I thought this too, but was too polite to say.

My money is actually on the system having no water in it. I've encountered this a few times over the decades and a boiler will send a surprising amount of heat along pipes full of air and even heating radiators a bit sometimes. Especially if an almost completely blocked cold fill pipe is delivering a drip of water every so often to create a but of steam. 

Unblocking the fill pipe and filling the system properly after being run empty sometimes reveals a cracked heat exchanger though. 

If the rear cabin rad is heating OK, that does point to the backboiler havin water in it.

Edited November 17, 2017 by smileypete

[tstore]

The system has water in it, whilst new to boating I do know this much. The rear rad, the last one in the system does get warm but it's the smallest one. The pipe then cross over to other side of boat and along the entire length to front, across and back back to normal back boiler. The pipe before it returns into back back is not very warm and assuming it's losing all the heat from this very long run and then the morso has to reheat it. If the back boiler takes half the heat to a really inefficient radiator set it would explain why I am grumbling.

 

So I guess the alternatives are to decommission back boiler. My neighbor did this and filled it with sand. Said it was the best thing they ever did or try and replumb a more efficient radiator system?

 

[bizzard]

7 minutes ago, tstore said:

The system has water in it, whilst new to boating I do know this much. The rear rad, the last one in the system does get warm but it's the smallest one. The pipe then cross over to other side of boat and along the entire length to front, across and back back to normal back boiler. The pipe before it returns into back back is not very warm and assuming it's losing all the heat from this very long run and then the morso has to reheat it. If the back boiler takes half the heat to a really inefficient radiator set it would explain why I am grumbling.

 

So I guess the alternatives are to decommission back boiler. My neighbor did this and filled it with sand. Said it was the best thing they ever did or try and replumb a more efficient radiator system?

 

There is a boat here 65' long with a Morso with back boiler and long pipe loop which had radiators that didn't get very warm at all, I took the rads out and connected all the in and out's of their pipes together and it now thermo syphones perfectly and gets lovely and warm now throughout the boat and no more messing getting trapped air out of rads.  As I said in my previous post just a pipe loop was the original way it was done on boats whether a solid fuel stove or gas boiler like the old Alde Comfort was used.

[MtB]

On 18/11/2017 at 11:25, tstore said:

The system has water in it, whilst new to boating I do know this much. The rear rad, the last one in the system does get warm but it's the smallest one. The pipe then cross over to other side of boat and along the entire length to front, across and back back to normal back boiler. The pipe before it returns into back back is not very warm and assuming it's losing all the heat from this very long run and then the morso has to reheat it. If the back boiler takes half the heat to a really inefficient radiator set it would explain why I am grumbling.

 

So I guess the alternatives are to decommission back boiler. My neighbor did this and filled it with sand. Said it was the best thing they ever did or try and replumb a more efficient radiator system?

 

 

The stove is rated at 5kW output with it glowing hot and jumping off the hearth, but only about 2.0kW of this goes into the radiator circuit.

2kW is plenty of heat to boil the water so as your system water isn't boiling, we know you are still being unnecessarily timid with getting it roaring hot. If you don't get it roaring hot, the rads will never heat up. 

A roaring hot stove will either heat up the rads brilliantly or be spitting steam out of the vent pipe. Your does neither so it can't actually be that hot.

[smileypete]

134ft of 22mm copper will lose up to 2kW of heat (40m x ~50W/m linky).

So Bizzard is right, the pipes alone will take all the backboiler heat with the fire on full output!

Seems like the main options might be to reduce the size of the system considerably, or take the backboiler out/fill with sand (and leave uncapped!)

Depends where you want the heat I s'pose. IIRC a typical 2 ft by 2 ft. double rad with one set of fins will output 1kW of heat when hot, so each square ft takes about 250W of heat.

 

Edited November 18, 2017 by smileypete

[tstore]

47 minutes ago, bizzard said:

There is a boat here 65' long with a Morso with back boiler and long pipe loop which had radiators that didn't get very warm at all, I took the rads out and connected all the in and out's of their pipes together and it now thermo syphones perfectly and gets lovely and warm now throughout the boat and no more messing getting trapped air out of rads.  As I said in my previous post just a pipe loop was the original way it was done on boats whether a solid fuel stove or gas boiler like the old Alde Comfort was used.

Does the system referred to above still need the pump to circulate?

[bizzard]

4 minutes ago, tstore said:

Does the system referred to above still need the pump to circulate?

No.  The beauty of it is that to keep the pipe loop nice and warm throughout you don't need the stove roaring away like crazy because as Smiley Pete said, that by omitting the rads the heating area of the system is reduced to a point where the limited output of the Morco back boiler can cope easily with the stove stoked up and running reasonably hot. Running a Morso flat out, roaring away like a loony is likely to crack the cast iron and will burn out fire grates regularly.

[Slim]

Tstore,

After reading this topic yesterday morning I went to the boat to do some work on it. Out of curiosity I lit the Morso and checked temperatures over several hours.

VS is a 22 year old 55' semi trad that I fitted out from a bare shell so I know it's specs well. Underfloor is insulated with 2" foam. Hull sides are insulated with Rockwool behind 12mm ply that has a surface covering of 4mm cork tiles. Cabin sides are Rockwool lined with 9mm ply overlaid with 4mm oak ply. Roof is Rockwool overlaid with 4mm ply. Front doors / windows are double glazed. Side windows are 11" single glazed ports. The roof has 2 single glazed Houdini hatches both in the living / kitchen area. The living / kitchen / dinette area is open plan and approx. 28' in length. The stove is located about 10' from the front doors.

Temperature readings were as follows. On arrival the outside according to the car was about 4c There was still a frost on the grass (apologies in advance for mixed C / F units )

 

Time  11 00        

Boat  39F / 4C      Middle of living area at chest height

Rad  2.5 C            Taken with IR thermometer

Time  12.00

Boat  56F / 13C

Pipe to 1st rad 20C   Top of 1st rad 40C,  bottom of rad 23C  (yes, those are the readings I took)

Time  12.30

Boat  63F / 19C

Pipe to 1st rad 37C,  Top of 1st rad 50C,  bottom of rad 20C

Time  13.00

Boat  63F / 19C

Pipe to 1st rad 41C,  Top of rad 51C,  bottom 31C

Time  13.35

Boat 70F / 21C

Pipe to 1st rad 37C,  Top of rad 48C,  bottom 25C

Note. The stove was lit, fairly gentle heat followed by about 12 lumps of smokeless (guess) with bottom door ajar for a few minutes then closed and bottom air about half open. No further fuel was added.  Yes, I do have an Ecofan but no claims made ,

Hope this is of some help

 

Frank

Should add that a) can't guarantee accuracy if IR thermometer and b) water circulation was thermo not pumped 

 

 

 

Edited November 18, 2017 by Slim

[tstore]

53 minutes ago, bizzard said:

No.  The beauty of it is that to keep the pipe loop nice and warm throughout you don't need the stove roaring away like crazy because as Smiley Pete said, that by omitting the rads the heating area of the system is reduced to a point where the limited output of the Morco back boiler can cope easily with the stove stoked up and running reasonably hot. Running a Morso flat out, roaring away like a loony is likely to crack the cast iron and will burn out fire grates regularly.

This sounds very appealing and logical to me. Do you leave header tank in?

[bizzard]

6 minutes ago, tstore said:

This sounds very appealing and logical to me. Do you leave header tank in?

Oh, yes. The one I did also had an Alde Comfort boiler in the circuit too which they never ever used, that is removed now as well. Tony Matts of Foxton boat Services was one of the main designers of the Alde comfort type of gas boilers. His old Harborough Marine hire boats ranging from a 36 footer to a 70 footer all had the heating pipe loops with no rads.

[tstore]

Hi all

 

Thanks for all the advice last November, I managed to get through a cold winter by supplementing with electric heating.

 

I'm back with more questions about my back boiler set up. During the summer I cleared out the crap from what had dropped on heat exchanger, there was quite a lot. I drained the whole system down and replaced with new coolant. I took the first radiator out in the system and flushed it. I also fiddled with the values on the last radiator to reduce the flow through the radiator. This has improved the heat generated in the first radiator but the towel only gets warm, not hot, like the first and last radiators. Should I reduce the flow even more in the last radiator? How much can the reduce the flow without causing the any problems?

 

Thanks again for advice, it is greatly appreciated.

 

[Jen-in-Wellies]

Welcome back.

Can you post some pictures of your system? Ideally a diagram showing pipe runs, pipe lengths, diameters and radiator sizes, valve and pump locations as well. This would really help us understand what is going on and save a lot of time. I've re-read the thread and still don't really understand how your heating circuit is plumbed.

Just a an example, here is one we did for a former neighbours boat after we sorted out some problems it had with circulation around the header tank and calorifier region. I've removed the boats name. It doesn't have everything, pipe sizes lengths and the radiator valves. This boat had a Squirrel stove heating a calorifier a towel rail and a radiator via a pump and was toasty warm through the winter.

My boat also has a Squirrel, calorifier and two finrads, but is gravity circulated and again is toasty warm.

 

Jen

Edited November 8, 2018 by Jen-in-Wellies

[tstore]

Hi I've attached for a start a diagram of the system with has a 12v pump in it. Got it nice and hot tonight, all pipework is hot but towel rail is not. Any advice welcome. As I said reducing flow by adjusting lock shield valves on back radiator has helped but still can't get towel rail heated.

[rusty69]

Bin the towel rail, replace with rad? My squirrel supports 3 rads, no towel rail no pump.

[tstore]

Ok what size rad could I put in its place?

 

[Boater Sam]

As a heating designer (retired) I can make the following observations.

 

1   Single pipe circuit such as this are sluggish and not efficient. The radiators will be cooler as the water goes round the system.

2   The flow (hot) pipe dropping to the floor from the boiler seriously reduces any flow due to gravity, hence the pump. I detest pumped solid fuel fired systems on safety grounds.

3   On single pipe systems it is advantageous that the flow pipe to each radiator  goes to the top of the radiator. Using opposite bottom connections drops the radiator efficiency by 7%.

4   When dealing with boilers that are underpowered for the heating load as in this case it is an advantage to be able to turn off any radiator that does not need to be on.

5  Thermostatic valves are a no-no on such a system.

6   Running a gravity only system is the best way to use a solid fuel boiler. The flow pipe rises from the boiler to gunwale height, feeds the radiators at the top, return from the opposite bottom corner, return at low level to the boiler.

7 My system has a Squirrel at the rear of the saloon 14 ft from the front door feeding a 134litre vertical calorifier, 3 radiators with thermostatic valves, no lock shields, and a pipe loop to the front of the boat to prevent condensation on the water tank. All pipework is 15mm, all gravity circulated in a 50' boat with 3 Houdinis, 4 single glazed windows, 4 small double glazed ports, side doors. No insulation in the floor, 2" polystyrene in walls and deckhead. It burns 100kilos of anthracite/egg mix every 2 weeks in winter and is toasty.

Sam.

Edited November 8, 2018 by Boater Sam
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