vaillant turbo max vuw 242 E

[paul683565]

HI all

i have a vaillant turbo max VUW 242 E ,date of manufacture is 1998 ,it is being used in a commercial premises and is subject to very high hot water demand.and small heating load of six small rads

it is serviced religiously . i have found that diverter valves are only lasting 9 months at the most , i have fitted a new one today. our problem is maintaining consistent hot water temperature.
The dial on the boiler is set to 8 and the boiler temp gauge shows just over 80 degrees ,system pressure is regularly checked and is 1 bar .

the only way i can get the water temp reasonably high is to partially close the flow restrictor controlling flow of cold mains water into the diverter valve ,currently it is just over 1/4 turn open .any less than this and there is not enough pressure to open the diverter valve fully and make the diverter valve micro switch .any more and the flow rate appears too great for the DHW heat exchanger to cope with and the hot water becomes progressively colder .i have adjusted the position of the switch and it now works.

can any one tell me how to set up the position of the switch correctly and how far open should the flow restrictor be set .

many thanks

 

[Netdragon]

This boiler is more designed for home domestic property's and can provide 8 litres/min with 35 degree c rise use a Weir cup can obtain them from a plumbing shop, and check the flow rate if its spot on and the temps 35 rise from mains inlet temp then boiler is working ok who ever installed it did not correctly size the boiler.
get a nice limescale filter onto your mains and a magno clean for your central heating this goes on the return this will help problems with the valves failing due to limescale or sludge/magnotite in the system.


You could upgrade to a Ideal Logic + 32 i think it is model that gives you 15 l/m and may meed demand.

Should not realy be adjusting the pins to the micro switches but if its in full and u can make them switch without masive adjustment and shuts off ok but get your engineer to check it on the next service asap.

 

[bellairaphon]

get a small unvented cylinder be more practica. and put it onto the combi wiring in a s plan

Nath

 

[Agile]

To put the matter into perspective could you outline what the hot water is used for and how many days/hours?

Even in restaurants I have seen combi boilers working without much of a problem for years on end without failing the diverter valve much more often than in homes.

Tony

 

[Temprise]

The diverter valves on these boilers were and still are a weak point. If used in a comercial premisis i imagine that the diaphram wears out very quickly.

Regards

 

[nogoodatfaultfinding]

This boiler is more designed for home domestic property's and can provide 8 litres/min with 35 degree c rise use a Weir cup can obtain them from a plumbing shop, and check the flow rate if its spot on and the temps 35 rise from mains inlet temp then boiler is working ok who ever installed it did not correctly size the boiler.
get a nice limescale filter onto your mains and a magno clean for your central heating this goes on the return this will help problems with the valves failing due to limescale or sludge/magnotite in the system.


You could upgrade to a Ideal Logic + 32 i think it is model that gives you 15 l/m and may meed demand.

Should not realy be adjusting the pins to the micro switches but if its in full and u can make them switch without masive adjustment and shuts off ok but get your engineer to check it on the next service asap.

Trust me mate it would be far cheaper/wiser and better practise to keep changing the diverter on your current setup than waste your money on the Ideal Logic DO NOT GO NEAR IDEAL!!!!!

 

[paul683565]

To put the matter into perspective could you outline what the hot water is used for and how many days/hours?

Even in restaurants I have seen combi boilers working without much of a problem for years on end without failing the diverter valve much more often than in homes.

Tony

hi tony

thank you for your reply ,the diverter valve was replaced yesterday ,the boiler is used in a mid sized health spa and is filling baths 7 days a week 12 -14 hours per day it does alot of work. but is serviced regularly,i have called the vaillant technical help line who now suggest changing the DHW heat exchanger, i have one on order.usually the only thing that goes wrong with this boiler is the diverter valve failing every 9 months or so. but its something else this time .

if open up the flow restrictor to controlling mains cold water to the DHW heat exchanger the hot water temp drops away quickly ,if i close the restrictor more there is not enough flow to keep the Diverter valve open and the boiler again wont give hot water , CH is always working fine .

i did notice the inside of the old Diverter valve was very black

hope this helps

paul 683565

 

[Netdragon]

Very black, is a sign of magnacite in the system basicly the radiatoers rad valves copper tube are all rusting against each other and this is causing strain on your boiler.

Its worth considering a Magno clean for your system it has a big magnet that grabs all this metal fragments and stops it hitting your boilers internal parts and you can clean it your self.

 

[Agile]

Whilst I would love to help you I would need solid scientific evidence.

DHW flow rate.
Inlet / outlet temperatures
Gas rate

Tony

 

[paul683565]

To put the matter into perspective could you outline what the hot water is used for and how many days/hours?

Even in restaurants I have seen combi boilers working without much of a problem for years on end without failing the diverter valve much more often than in homes.

Tony

hi tony

thank you for your reply ,the diverter valve was replaced yesterday ,the boiler is used in a mid sized health spa and is filling baths 7 days a week 12 -14 hours per day it does alot of work. but is serviced regularly,i have called the vaillant technical help line who now suggest changing the DHW heat exchanger, i have one on order.usually the only thing that goes wrong with this boiler is the diverter valve failing every 9 months or so. but its something else this time .

if open up the flow restrictor to controlling mains cold water to the DHW heat exchanger the hot water temp drops away quickly ,if i close the restrictor more there is not enough flow to keep the Diverter valve open and the boiler again wont give hot water , CH is always working fine .

i did notice the inside of the old Diverter valve was very black

hope this helps

paul 683565

further to the above the domestic hot water heat exchanger has now been replaced to try to cure a new fault which has developed ,whats happening now is a loss of system pressure when hot water is called for as above a new diverter valve was fitted a few days ago and a new DHW heat exchanger ,how can it loose system pressure as two of the major components in the boiler are new ,all rads etc were bled when the new components were fitted and all seems normal until hot water is used ,if used repeatedly the system has to be topped up almost daily ,i suspect i have been sold a faulty div valve ....? any ideas

paul 683565

 

[Agile]

Is this a brand new diverter valve or some kind of dodgy repaired part?

Have you checked the charge pressure in the expansion vessel lately?

In such a small system I dont see why there should be so much black oxide in the heating circuit? Was/is it regularly properly powerflushed or otherwise treated?

Tony

 

[Netdragon]

there should be a pipe from the boiler that runs to the outside which is your pressure release pipe from your prv it could be the guy you had out used this to drain your boiler.

Check it by seeing if the pipe has water inside it outside.

If it does he probably used the prv to drain it and now some dirt is holding it open and may need a replacement