Vaillant ecotec plus 438 no heating or hot water

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Well, if its happening like that and you still have 230V at the SL then does look like the fault is at the boiler end.
Have you ever purchased a refurbished pcb? They're alot cheaper but it's the risk of it not being new which are £250 circa.

Would the pcb part number be on the back of it? Seen some online photos of pcb but can't see the matching part number as on the description
 
This morning had the f23 code.

It is a new pump, am assuming the code may be due to it being on the lowest setting?

When CH and HW are on, the rads don't get that hot. The gate bypass valve is also open.


The light bulb was lit at the boiler SL
 

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Has the boiler been running OK since Mon last?
Why is a manual bypass needed or installed? it's a Y plan.
You renewed the pump very recently what make/model? UPS3?
 
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The UPS3 even set to speed1 (4.2M) still circulates up to 12.5LPM at this head, 16.67LPM at a 3.6M head and 21.7LPM at a 3.0M head which should be quite adequate, you can allways change it to constant pressure CP 2 which will pump up to 32.5LPM at a constant 4.5m head but this may cause noise or pump over into the feed and expansion cistern if you have a open vented system.

Where is this manual bypass installed?.
 
The UPS3 even set to speed1 (4.2M) still circulates up to 12.5LPM at this head, 16.67LPM at a 3.6M head and 21.7LPM at a 3.0M head which should be quite adequate, you can allways change it to constant pressure CP 2 which will pump up to 32.5LPM at a constant 4.5m head but this may cause noise or pump over into the feed and expansion cistern if you have a open vented system.

Where is this manual bypass installed?.
After the pump but before the 3 port valve.

Do these only have a quarter turn to open and shut?
 

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If you mean the brass/bronze valve immediately after (and another before) the pump, these are the pump (suction and discharge) isolating valves and are 1/4 turn ball valves, these should be fully open at all times except when changing out the pump.
The red wheel (gate) valve requires ~ 3 full turns to fully open and the same to shut, if this is currently shut and you try to open it (anticlockwise) then you will feel resistance initially then possibly no resistance for a 1/4 turn so and then moderate resistance while fully opening it. What is it bypassing?, it seems to be teed in just after the pump at one end..... whats at the other end?. Is it open or shut?.
It does look like a bypass between the boiler flow and return, might require say a turn open if you have TRVs installed.

Have you a open vented with a small feed&expansion cistern in the attic or a sealed system with a red expansion vessel somewhere?.
 
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If you mean the brass/bronze valve immediately after (and another before) the pump, these are the pump (suction and discharge) isolating valves and are 1/4 turn ball valves, these should be fully open at all times except when changing out the pump.
The red wheel (gate) valve requires ~ 3 full turns to fully open and the same to shut, if this is currently shut and you try to open it (anticlockwise) then you will feel resistance initially then possibly no resistance for a 1/4 turn so and then moderate resistance while fully opening it. What is it bypassing?, it seems to be teed in just after the pump at one end..... whats at the other end?. Is it open or shut?.
It does look like a bypass between the boiler flow and return, might require say a turn open if you have TRVs installed.

Have you a open vented with a small feed&expansion cistern in the attic or a sealed system with a red expansion vessel somewhere?.
Open vented.

The red gate valve is open, I will have to check where it goes. If this is open I assume there will be less hot water being pushed for heating and hot water.
 
If its very hot then it is bypassing the water from the boiler flow (via the pump) back into the boiler return, can't really see any need for it with a 3 port valve.
 
If its very hot then it is bypassing the water from the boiler flow (via the pump) back into the boiler return, can't really see any need for it with a 3 port valve.
Hi John,

Thanks for your time and tenacity on this thread.

The issue appears to have resolved after I checked each wire. Some wires had discolouration on the copper so I stripped fresh copper, and replaced the wiring centre with a Wago one which is much easier and ensures every wire is solid in its block.

The terminal blocks are a pain and the flex does become spiralled and therefore there is a lack of copper in the connector.

I've also replaced the connector blocks by the boiler with ideal Connectors (similar to wago).

The boiler and pump kick in immediately now.

The issue was likely due to poor conductivity.

Cheers
 
If that fixed it, that would usually be described as poor connections, or terminations.
They can't come loose over the years by themselves.

As stated some of the copper was discoloured, I did post one wire that was silver at the programmer.

The wago connectors (or anything similar) is the way forward. Ideal Connectors are better but ideal don't make a junction box, bit daft really. Even if it doesn't come pre fixed like the wago box, a plain box with inserts would be great.
 

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