iBoost problems

MrBullfinch

I recently had solar panels and iboost installed. I hoped to use the iboost to probably heat all my water in summer and certainly it was a good way of effectively storing some of the energy from the panels. I am disappointed to discover that only a little energy is being stored in the tank. It quickly reaches WATER HOT message. I turned the immersion thermostat up to 65 and the main tank thermostat (for the gas boiler) down to 45. I now realise that the immersion is only 11 inches, which only the top of the tank, adequate for a shower or a sink of washing up but not to last overnight for a shower next morning. I am not sure whether it is worth changing the immersion for a longer one (27ins?). Comments, advice, suggestions?

Verdigris

Is there a second immersion flange near the bottom of the cylinder? If so, just move the current one to there, or fit a second, possibly larger, one.

If no second flange then a longer element should do the trick.

QrizB

A short immersion isn't unusual for a tank where the main heating source is expected to be a gas boiler.

As Verdigris says, fitting a longer element will solve the problem.

Reed_Richards

Verdigris said:

If no second flange then a longer element should do the trick.

How does that work?  Isn't the immersion heater horizontal inside the tank?  Isn't the water stratified?

QrizB

Reed_Richards said:

Verdigris said:

If no second flange then a longer element should do the trick.

How does that work?  Isn't the immersion heater horizontal inside the tank?  Isn't the water stratified?

For a tank with horizontal heater element(s), yes. However most of the indirect tanks I've seen have the immersion heater in the crown of the tank, rather like this one:

With a tank like this, a longer element will extend further into the tank and heat more water.

tim_p

Where’s the immersion fitted?  If it’s downwards from the top then a longer one (27”) should fit and solve the issue however, as others have mentioned, if it’s a short one fitted horizontally at the top then a longer one isn’t going to work (or even fit unless the tank is huge!). Is there a second immersion about a third of the way up from the bottom of the tank?
Be aware, if the immersion is a vertical (ish) one and it’s been in for a long time you (or even a decent plumber) might struggle to actually successfully remove the old one without damaging the tank. 

If the iBoost doesn’t give any heat then the immersion or thermostat might be faulty, so worth checking first. 

Verdigris

However most of the indirect tanks I've seen have the immersion heater in the crown of the tank, rather like this one

Yes, I was assuming the flange was in the crown.

But we all know aboute assume!

MrBullfinch

The heating element is indeed in the crown and the system (about 25 years old) was primarily for a gas boiler. I have almost never used the immersion previously. If changing the element could possibly be difficult and damage the tank then it is probably not a good way to go. Currently, using iboost will save gas and therefore money but it is commensurate with the SEG tarif. So, it does not matter so much. However, I am assumimg that gas prices will rise considerably soon.

Dave_Fowler

MrBullfinch said:

The heating element is indeed in the crown and the system (about 25 years old) was primarily for a gas boiler. I have almost never used the immersion previously. If changing the element could possibly be difficult and damage the tank then it is probably not a good way to go. Currently, using iboost will save gas and therefore money but it is commensurate with the SEG tarif. So, it does not matter so much. However, I am assumimg that gas prices will rise considerably soon.

Another solution would be to instal a recirculation pump which turns on when the immersion heater thermostat opens.  The pump would take the hot water from the top of the tank and pump it into the bottom inlet where the cold water feed from the loft storage tank arrives.  The pump comes on when the immersion thermostat open and goes off as soon as it closes again as the recirculation causes the water to cool.  I've had this system for years - it ensures the top of the tank is always hot, and on sunny days the entire tank is raised to the immersion thermostat temperature.

Dave F

NoobSolar

I boost is capable of operating two immersion heaters. Ideal to have it heat the bottom first then the top, if your cylinder has two in that way.

Reed_Richards

Dave_Fowler said:

Another solution would be to instal a recirculation pump which turns on when the immersion heater thermostat opens.  The pump would take the hot water from the top of the tank and pump it into the bottom inlet where the cold water feed from the loft storage tank arrives.  The pump comes on when the immersion thermostat open and goes off as soon as it closes again as the recirculation causes the water to cool.  I've had this system for years - it ensures the top of the tank is always hot, and on sunny days the entire tank is raised to the immersion thermostat temperature.

Dave F

A destratification pump is probably a more correct term, a re-circulation pump would typically send the hot water round the building and back to the tank.  You would need a one-way valve on the cold water inlet so the pump did not pump the cold water the wrong way down the pipe.