Ecotec Plus Combo Boiler


When I put the boiler on, the gauge is going in the red, is this bad should i worry about it or can I do anything to put it right. Please can you help. Thank you.


Hi Ian,

This can be serious problem especially if your system relief valve is defective.  High pressure is typically caused because there is either too much water in the boiler circuit or trapped air.  You can drain water off at the dump valve located near the boiler.  Alternatively you can drain water off at the vent located on one of your radiators.  The highest radiator is best because you will be able to see if trapped air in the system is causing the issue.

Ecoplus 831R1 Problem

The bar pressure keeps going into the red. I regularly drain off excess water. It has been proven that water is not entering via the double filling valves. How else can the system fill itself and if it is a faulty part what costs are involved to replace same.




Hi James,


You could simply have trapped air in the system.  This will cause a high pressure at the gauge.  Open the vent at your highest radiator checking for trapped air.

When you state that water is not entering via the double filling valves do you mean it is not possible that the valves are defective allowing water to pass?  Remember if a valve is defective it can still indicate that it is closed but it is passing water.  Although unlikely you could also have a faulty pressure gauge.

Try shutting the boiler down completely and waiting until the water temperature has equalised.  Drain any water off such that your boiler circuit pressure is less than the mains water pressure on the other side of your filling valves.  Check the pressure gauge over a period of time to see if it is increasing.  If it is then you have defective filling valves that are passing water.

Vaillant 828 Boiler F20 Code

My boiler keeps showing the following code when trying to run the central heating F20. Wondering if you have any ideas how this can be fixed?



Hi Chris,

The F.20 fault code for an EcoMAx 828 is a safety protection cut-out due to high water temperature.  During normal operation the boiler will heat the water until it reaches a maximum set temperature and cuts-out the burner circuit.  If this normal cut-out fails, the boiler will continue to heat the water until the final safety protection cut-out energises and shuts off the boiler giving you the F.20 Fault code.  Therefore in your case the maximum set temperature cut-out is not working.  This could be a controller issue or a defective temperature sensor / cable.  This is a serious issue and should be looked at by a qualified service engineer.

Eco Tech Plus 618 Heating Problem

The boiler is about 2 years old, water is heating up ok but when heating the radiators it will not reach desired temp and gets to about 20.5 to a max of 21.5 even if i set temp for 25.0. I have spoken to vaillant help line who talked me through reset, and there are no fault codes displayed. Any ideas?



Hi Steve,

There could be a number of issues with this scenario as you have stated it.  How are you measuring the temperature at the radiators?  In the past has the boiler managed to heat the room up to 25 degrees ok?  It may be related the the selection of your boiler in the first place.  You may have an issue with the controller, thermostat or temperature sensor.  More information please.

Vaillant Ecomax 828e Combi Boiler Parts

The above boiler uses a pair of packingrings part number 980151 on either side of the water filter. I could not find that part number being sold around on the internet. Has it been replaced by another equivalent part number?

Kind Regards,


Hi David,

I had a quick look on the internet and found the sealing ring part either side of the filter to be 981140.

Vaillant Ecomax 828e Combi Boiler

The heat exchanger insulation kit 210734 in the above comes with two door insulations. One is a perfect fit on the above boiler but the other not so perfect. Can the second one be used? Why does the kit supply two of them?



Hi Roger,

Although I am not 100% certain on this it could be that you have an insulation kit for both the primary and secondary heat exchangers.  Hence why you have two insulation packages.

Vaillant Boiler Water is Cold after 5 Minutes

Water gets cold every 5 minutes or so for a couple of minutes in sink and shower. Any ideas?



Hi Patel,


I need more information about your issue before I can help.  What type of boiler do you have?  Are you seeing any fault codes?

Valliant ECO BLUE 837 Water Cold

Boiler is fitted in first floor kitchen. Hot water changes to cold after about 5 min from hot to cold for 2 to 3 min in kitchen sink and shower on the first floor same happens during shower on 2nd floor as well. Engineer changed adapter valve 0020132682.
Problem is still not solved.
Please help


Hi Andrew,

Without further information it is difficult for me to diagnose.  Are you seeing any fault codes?

Eco Tec Pro 28 Fault

I had a boiler fitted February this year type valliant eco tec pro 28. The small white box on wall next to boiler keeps tripping therefore the boiler does not work for the radiators, yet I can still get hot water from the boiler, whats going on here with the boiler?


Hi Dan,

The small white box on the wall is the Controller.  If this control unit is tripping then you have an electrical fault that needs to be investigated and corrected by an electrician.  A fault in this box would definitely prevent hot water from traveling to your radiators.  You are still getting hot water to your taps, showers etc because you have a combi boiler and this functionality is not controlled by the control unit.

Eco Max 613/2e, does it have a built in auto by-pass

I am installing a pressurised hot water system. My gas boiler is an Eco Max 613/2E, is it fitted with a built in auto by-pass? Or will I need to fit an external one. The seriel no of the boiler 2105333051620001006075N (last D or O)

Thank you for Your help



Hi Daniel,

Indeed the EcoMax 600 series is fitted with an automatic bypass valve.  You can see it in our exploded parts list, please see link below:

EcoMAX 613/2E