Alde Comfort 2928 Maintenance and Problem

[Swilson]

Hello,

 

Its a great time of year to have a problem with the boiler!

 

We have an Alde Comfort 2928 which is about 15 years old, we have been on the boat for 2.5 years.

 

Question 1: What maintenance routine should I be following with the boiler to make sure it is well maintained?

 

Question 2: On the 23rd quite late at night I heard the boiler making a big gurgling sound and went to have a look and water had 'boiled over'. The reservoir with the pump attached was hotter to touch than what I remember of winters past. I checked the water level and it was just above minimum, I gave it a little top up (but with water rather than 50:50 antifreeze as I know now). 

 

What could be the possible causes of the problem? Anything other than these? And ate there other solutions to look for?

- Antifreeze level too low?

- Antifreeze too old - need to pump out old water and to refill with 50:50

- Faulty thermostat - needs replacing?

- Faulty pump - need replacing?

- Airlock in rads - bleed the whole system

 

Question 3: Does the antifreeze keep the temperature of the liquid down and therefore stop it from boiling over? Or does it just stop the liquid from freezing in cold conditions?

 

Many thanks in advance!

[David Mack]

1. Mine benefitted from removing the burner assembly (a complete performance given the way the boiler was built into a cupboard), and giving it a good clean to remove all the cobwebs and other crap blocking the burners.  It was much easier to light after that.

 

2. No water circulation. So, assuming the pump is still working, filling the header tank should have sorted it. You might also need to bleed the radiators, in which case you will then need to top up the header tank again.

Edited December 27, 2020 by David Mack

[BEngo]

1.  Follow the manufacturers recommendations.  A good clean of the burner and heat exchanger annually and a check that the air intake and exhaust are clear seems to be about all they really need.  The inlet and exhaust can be prone to spider takeover during the warmer months.

2.  The pump is not taking the hot water away from the boiler fast enough.  Either the pump has failed/ been slowed down  or the flow through the pipes is restricted.  Check all the radiator valves are fully open and the rads are all bled.

3.  The glycol in Antifreeze does help with heat transfer, but should not be vital to stop the system boiling.  Antifreeze is thrre for twocreasonsz: to prevent the system in cold spells and to reduce corrosion in the system.  The corrosion inhibitors are the reason for changing it as they get used up.

 

N

 

[Tony Brooks]

Antifreeze actually carries less heat than water but a song as you say wth 50% or maybe 30% is better don't worry about it.

 

Antifreeze its self will last for years, it the corrosion inhibitors that get "used up" so if its blue antifreeze and has been in longer than two years or so it needs changing but it did not cause your problem. You don't normally pump it out unless you put a pump on a central heating drain point. Its a full system drain and i would suggest flush several times with clean water before  refilling with MIXED antifreeze - water mixture.

 

If its been working OK since the incident it is very unlikely to be a thermostat problem although I would have expected the "button" style overheat stat to have cut the boiler out. Its held onto the cylindrical boiler case by a spring. Make sure it is still holding the button in place.

 

I suspect the water level is far lower than you think, in fact just at the bottom of the impeller so it just spun and gurgled.

 

The maintenance is basically keeping the pilot light burner free of fluff and dirt & ensuring the pilot light does not deposit carbon on the  probe by it. Then ensure the main burner air holes are clean.

 

 

 

 

 

Just now, BEngo said:

1.  Follow the manufacturers recommendations.  A good clean of the burner and heat exchanger annually and a check that the air intake and exhaust are clear seems to be about all they really need.  The inlet and exhaust can be prone to spider takeover during the warmer months.

2.  The pump is not taking the hot water away from the boiler fast enough.  Either the pump has failed/ been slowed down  or the flow through the pipes is restricted.  Check all the radiator valves are fully open and the rads are all bled.

3.  The glycol in Antifreeze does help with heat transfer, but should not be vital to stop the system boiling.  Antifreeze is thrre for twocreasonsz: to prevent the system in cold spells and to reduce corrosion in the system.  The corrosion inhibitors are the reason for changing it as they get used up.

 

N

 

 

Check the specific heat capacity of Glycol and water.

[StephenA]

 Even at 9 with the pump turned off the water should never reach boiling point. Even if the main thermostat fails there is an overheat sensor on the main boiler unit which should cut things off.

 

Our optimus has taken to mis-behaving if you turn the burner much above 5 and it's starting to get unreliable, but the problem is that there is no obvious drop in replacement for it.

[Opener]

Have a good look at the water reservoir on top of the boiler case.  The pump is held in place with the screwed collar and the impellor sits way down in the bottom of the reservoir.  A bit difficult to see but is the small space around the impellor clear?  A couple of times I've had to remove a load of cr@p from mine - just bought a knickerbocker glory spoon to aid in future cleaning.  You may have disturbed a blockage there in moving the pump/topping up and that may recur.  I'm guessing a pump stoppage may cause your symptoms.

[StephenA]

3 hours ago, Opener said:

Have a good look at the water reservoir on top of the boiler case.  The pump is held in place with the screwed collar and the impellor sits way down in the bottom of the reservoir.  A bit difficult to see but is the small space around the impellor clear?  A couple of times I've had to remove a load of cr@p from mine - just bought a knickerbocker glory spoon to aid in future cleaning.  You may have disturbed a blockage there in moving the pump/topping up and that may recur.  I'm guessing a pump stoppage may cause your symptoms.

 

The thermostat and the over heat should stop it boiling over. As I  said you can run an Optimus on it's highest burner setting with the pump turned off and it won't boil over. The max temp it should reach is 75C. If the header tank is over full then it should vent down the overflow pipe.  So if it really has boiled over then that suggests 2 things :

 

1) Primary thermostat is faulty

2) Overheat cutout (separate sensor) is faulty.

[Ewan123]

Number 2 is what ours does (when heated by the connected mutifuel stove) if the pump hasn't started and the hot water isn't being circulated through the radiators. I know it's a bit different, but I'd make sure that the pump is definitely pumping the hot water around the radiator system.

Edited December 27, 2020 by Ewan123