Megaflow - thermostat hot water problem

[katelthompson]

Hi

I have a megaflow system with an immersion heater. At the moment I can not get enough hot water to have a hot bath. I only get enough hot water to fill the bath to about 3.5 inches.
A plumber who is experienced in megaflow systems came out to look it and replaced the main thermostat element in the system but this has made no difference at all. I am still getting the same amount of hot water which is no where near enough to have a bath!

Can anyone help? or make any suggestions as to what the problem could be?

Thanks

 

[steved101]

does water run from the top tap after 3 inches or so, or does it stop flowing?

 

[Silinman]

Is the main relief valve dripping or discharging water via the external vent pipe?

Have you tried re-generating the air gap?

 

[katelthompson]

do you mean hot tap? if so, the water keeps running but its just cold!

 

[picasso]

does your megaflo have 1 or 2 thermostats and do you know which one he replaced? and last question are you on economy 7 tariff.

 

[katelthompson]

the external vent pipe is dry so I can only assume it is not letting out water.

the plumber re-generating the air gap when he serviced the tank at the same time he replaced the thermostat. Neither of which have made any difference to the amount of hot water I am getting.

 

[katelthompson]

it has 2 thermostats and the plumber replaced the bottom one. I believe the top one is for the emersion heating which we have switched on at the moment - is that correct?

Yes, we are on the economy 7 tariff, although I have the hot water set to come on in the morning between 6-8 and at night between 6-10.

 

[picasso]

I thought that economy 7 ran from midnight till 7 , if your hot water is timed as you say it will "miss" the on period of the economy 7,the top element is giving half a tank of hot water so switch it off as its using peak rate electric, and double check the timer on the bottom element.

 

[katelthompson]

Thanks for the tip to save money, I'll make sure the main heater comes on during E7 time. I still don't understand why we are not getting enough hot water to run a bath.

 

[picasso]

Thanks for the tip to save money, I'll make sure the main heater comes on during E7 time. I still don't understand why we are not getting enough hot water to run a bath.

because the thermostat you have working at the moment is half way up the cylinder, it will only heat the water above it, (about half the cylinder)that is why you dont have a lot of hot water.

 

[katelthompson]

why doesn't the bottom thermostat work?

the bottom thermostat is linked to a timer that is set for non economy 7 times, I thought it would still work but it would cost us the higher rate of electricity. is that not right?

 

[picasso]

as I cant see your system its difficult to be definite but normally the bottom themostat only becomes live when the economy 7 meter switches it on

 

[katelthompson]

ok, thanks. I've set the timer to come on between 5-7am. Hopefully that will give us enough hot water. Will the water stay hot all day?

Does the bottom thermostat fill the whole tank? and the immersion thermostat fill the top half of the tank when the water is used up?

Many thanks for your advice!

 

[picasso]

on a normal economy 7 set up, there isint a timer ,the bottom element comes live when the economy 7 meter switches it on , the cylinder heats up from the bottom giving a full cylinder of hot water,when the water is hot enough the thermostat switches it off, the higher thermostat is a boost connected to the permanent expensive electricity available 24/7, hope this helps

 

[katelthompson]

back for more advice, last night we had the hot water set to come between 1-7am, and turned the emersion off. This morning the water was not very hot. Both the thermostats are set to 60degrees. Do you know why its not getting up to temperature?