I have a more modern well insulated house, buts it's good that you have got it running well I'm still fiddling, I suppose I'm trying to keep the return temp down but not get too much cycling.
Vaillant VRC 430f cycling issues - a solution?
- Thread starter Modokon
- Start date
I have a more modern well insulated house, buts it's good that you have got it running well I'm still fiddling, I suppose I'm trying to keep the return temp down but not get too much cycling.
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A
ALEC1
alot of the cycling is out door temperature dependent, it seems to be away of avoiding over heating... only the 400 series boiler (developed for the uk market) suffers in performance...
Which boiler have you?
A
ALEC1
i install all vaillant boiler .always with vrc 430
its a good bit of kit, the cycling issue is alteable in screen c21.. but it is there for a reaaon, and it can be altered for a reason
you dont want continuous firing at low loads...unless you have a low loss header and a variable speed pump with TRVs
its a good bit of kit, the cycling issue is alteable in screen c21.. but it is there for a reaaon, and it can be altered for a reason
you dont want continuous firing at low loads...unless you have a low loss header and a variable speed pump with TRVs
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Reducing D2 will increase cycling.. and it's not a set value. There are a few variables in the algorithm that will alter the anti cycle time so meddling with it, and especially lowering it will make it cycle more.
In addition some Ecotech boilers fire to much on start-up and this causes anti-cyling to kick in.
I have 4 Ecotech Plus boilers at various properties, 2 x 824, 1 x 831 and 1 x 937 and all start up in different styles. Some light up at low heat and then ramp up after a period and some light up on high heat and ramp down.
I assume this is because of software changes depending on the build date. Either that or more that one has the same fault.
All the boilers mentioned above share the same startup logical sequences. It's only the various systems they are attached to that will alter the behaviour.
Can you explain C21 please, the overshooting at startup is not a problem now it is colder but I would like to know how I can get the best out of the system when the weather starts to warm.
418 & 430
Thanks
A
ALEC1
What do you want to know... on the many installs I have done with vaillant I have never had to alter these except on a 438 where a client was having short cycling issues.
My advice really is to buy a thermemoter and measure room temperature that is the only real way of assessing the system's effectiveness.
As heating system's are different in all houses optimum settings will vary, vailalnt's just gives controls that work well in 99% of houses...
My advice really is to buy a thermemoter and measure room temperature that is the only real way of assessing the system's effectiveness.
As heating system's are different in all houses optimum settings will vary, vailalnt's just gives controls that work well in 99% of houses...
I am, I suspect, the 438 customer referred to in the post immediately above by ALEC1. I have been following this thread and others with interest since Alec added weather compensation (with VRC430f) in September to my existing 438, which was installed by others. Alec warned me before he started that there might be a cycling problem with these controls on this boiler, since another of his customers had already experienced it with his 428. So it proved.
Although I've only had these controls for three months or so, I've already been distinctly frustrated by the cycling. Having had no satisfactory response from Vaillant, that other customer and I have decided to start a website/blog about the cycling problem to try to share people's knowledge about it in a more structured way than on this forum, and to try to make Vaillant acknowledge that there is a problem - see http://vaillantcyclingproblem.blogspot.com/
We're trying to persuade people with the problem to fill in the form linked to from the page called "Info from owners with the problem". If you suffer from it, it would be great if you could contribute.
Although I've only had these controls for three months or so, I've already been distinctly frustrated by the cycling. Having had no satisfactory response from Vaillant, that other customer and I have decided to start a website/blog about the cycling problem to try to share people's knowledge about it in a more structured way than on this forum, and to try to make Vaillant acknowledge that there is a problem - see http://vaillantcyclingproblem.blogspot.com/
We're trying to persuade people with the problem to fill in the form linked to from the page called "Info from owners with the problem". If you suffer from it, it would be great if you could contribute.
The 438 is a cheapo Glowworm wearing smarter clothes. It goes out at a premium price but you only have to look inside to see you've been duped.
Vaillant have known about problems with these, including poor flow on the smaller units. I suspect there will be no solution other than the new open vent model due shortly. The 4 series will be old news from then, can't see them allocating development resource. The number of 4 series fitted with WC must be very small, after all, it was only soild in the UK.
We stopped fitting 4 series a few years back because the quality wasn't as good as their other models. Other manufacturers offer superior OV models, with WC if you must.
If the new one looks like a 6 series or an Ecomax then we'll have another look.
Beats me why you went with a 4 series and WC when you were told it wouldn't work properly by your chosen installer.
Vaillant have known about problems with these, including poor flow on the smaller units. I suspect there will be no solution other than the new open vent model due shortly. The 4 series will be old news from then, can't see them allocating development resource. The number of 4 series fitted with WC must be very small, after all, it was only soild in the UK.
We stopped fitting 4 series a few years back because the quality wasn't as good as their other models. Other manufacturers offer superior OV models, with WC if you must.
If the new one looks like a 6 series or an Ecomax then we'll have another look.
Beats me why you went with a 4 series and WC when you were told it wouldn't work properly by your chosen installer.
If the system is correctly installed, pump correctly specified and boiler correctly sized there is no problem. I've personally installed numerous GW Ultracoms which are all working fine and as you pointed out they are all but the same boiler. They are solid as any GS engineer will tell you. Every problem we ever came across was installer error. Usually inability to read the instructions, especially the bit about the heat exchanger resistance, which should indicate the type and speed setting of the pump to be used. But this kind of thing is alien to domestic installers who just want to chuck a box at a wall. The 3 Fs, Fit, Fire and F off.
9/10 or 99/100 problems with 400 series or g/w hxi's ar down to poor instalation, very few guys now have the skill set's to properly design a wet central heating system,
As micky has said lift unit to wall put in 7 pipes fill her up and get to bugger_y.
All is good and well in the combi market but even at that guys don't seem to realise that even 37 kw combi's require 28mm flow and returns.
one of the biggest issues are installers incopitence with something out of their league.
As micky has said lift unit to wall put in 7 pipes fill her up and get to bugger_y.
All is good and well in the combi market but even at that guys don't seem to realise that even 37 kw combi's require 28mm flow and returns.
one of the biggest issues are installers incopitence with something out of their league.
That and all the "tweaking" and "fiddling" with settings that people know very little of what they are adjusting and why they are doing it.
Speak to a decent installer and he'll tell you he has no issues with the appliances and controls.
Speak to a cr*p installer, and he'll tell you it's the shi**y boiler and that the manufacturer has programmed the controls incorrectly.... Horse sh*te
Course they have.... it can only be the logical answer....???? then they go and feed it all to the customer with Feck all to back it up, and they suck it in and blame the boiler too...
And just to top it off...... come up with answers on how to fix it....
Speak to a decent installer and he'll tell you he has no issues with the appliances and controls.
Speak to a cr*p installer, and he'll tell you it's the shi**y boiler and that the manufacturer has programmed the controls incorrectly.... Horse sh*te
Course they have.... it can only be the logical answer....???? then they go and feed it all to the customer with Feck all to back it up, and they suck it in and blame the boiler too...
And just to top it off...... come up with answers on how to fix it....
Poor flow through hex.
Poor quality condense trap.
Cabling arcs out against control box hinges.
Cheap gas valve.
All the above would be acceptable on a cheaper Glowworm. Vaillant boilers sold for Vaillant money should be better made, a fact shortly to be addressed, i'm told.
Like the three Fs, thats funny.
Poor quality condense trap.
Cabling arcs out against control box hinges.
Cheap gas valve.
All the above would be acceptable on a cheaper Glowworm. Vaillant boilers sold for Vaillant money should be better made, a fact shortly to be addressed, i'm told.
Like the three Fs, thats funny.
Actually, he recommended that we try it, and I still consider that to have been good advice. I already had the 4 series, before I'd ever even heard of weather compensation. It was therefore a choice of sticking with on/off controls for the life of the boiler (which was nearly brand new) or seeing if weather compensation would work. After all, it is supposed to work, according to Vaillant. And according to the doubters on this forum, it does work. So we decided to try it, in the knowledge that it might cause problems and might ultimately have to be abandoned. The idea of weather compensation is such a good one that I did not want to forgo the possibility of having the benefit of it for the next 10-15 years.
As for the doubters, I entirely agree with those who suggest that there are bad and ignorant installers around. However, there are also some very well-informed, knowledgeable and experienced ones. Mine happens to be one of the latter, who has installed perhaps hundreds of weather-compensated systems and has never had any trouble except with the two 400-series Vaillants that he has tried it with. And now that I have been collecting data with vrDialog, I have reams of data that show exactly how the boiler performs incorrectly under some conditions.
... as he doesn't stay there long enough to find out and/or blinds the 'customer' with science about how it's working as designed if he's called back!?
As a (technical) customer who understands his ecoTEC boiler and Vaillant controls more than most typical RGI's, I have to say that whilst there are common installation issues, there are circumstances (times of day and/or year) where the modulating controls do not work correctly. One such issue is known to the many Vaillant engineers on here (which I understand you are/were MrV?
) whereby the burner output is initially too high (first xx seconds), causing the boiler to cycle! To me, thats a Vaillant oversight/design issue caused by using the same software / system board on multiple boilers/valves/HE to save development costs. There are other issues with the firmware (which may be related to this issue) that cause the boiler to cycle more often than expected.
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