Question

Thank you. When I google images of lockshields, most don't have any arrows on them whereas TRV images do arrows. I also see a pair of valves that can be bought together, one TRV and the other lockshield, and it is only the TRV body that has arrows. Have you come across lockshields that are only good in one direction?

Are you saying that I should look at the lockshields at the other side of the radiator to where the TRVs are? I had a look at them and there are no arrows on any of them.

Now down to 1 radiator that does not have any markings on it and so I don't know whether it is bi-directional. all others are bi-directional. So can I forget about it. Water circulates fine through the Hot Water Coil.

10 radiators are bi-directional, another Danfoss where the direction selector was put in the wrong direction (by the engineer I have already mentioned), and the two other radiators have no markings whatsoever. Any advice please.

I have been trying to balance my radiators and found that most radiators first get hot on the lockshield side of the radiator. An engineer moved our boiler three years ago. I now believe he connected the supply pipe from the boiler to what was the return pipe and vice versa. Trying to correct this would involve moving the pump and changing the motorised valves, and costly. I think the easiest solution would be to make sure the radiators have bi-directional TRVs. Does this really matter and would checking the TRVs are bi directional be sufficient? (The engineer won't come back to sort this. On another matter, we got a defect notice issued against him by Gas Safe, and only then did he correct the fault, and I keep discovering other faults).

Thanks very much. I couldn't find a configuration like this when I googled (yes I have an unvented cylinder). If I drain the system, would I put both valves manually into open?

I have two motorised values in my heating system. One is a three port and the other is a two port. The three port has one flow pipe for the hot water and the other for the radiators. I would have thought that was enough, i.e. be a Y plan. However, there is also a two port valve between the three port and the hot water cylinder, and I can't understand why it is there. Picture below shows flow of water and 2 and 3 port motorised valves. Can you see a reason for the two port motorised valve?

Thanks for your reply. I had a look at VDI 2035 and it seems to be a standard to reach rather than a method of removing any corrosion. Can you please tell me what you did to reach VDI 2035 without powerflusing. (Regarding your question what am I trying to achieve. I just wanted to check what the plumber was saying, as many are happy to recommend more work for themselves).

A plumber told me that I need a poweflush. I took some water via a bleed value of a radiator. It is slightly brown/orangey. I took a photo and it is against a very white background in good light. Do I need to powerflush? I would be grateful for your thoughts.

thanks for your replies. More expense probably as it will be very difficult to get the original installer back. Any thoughts about how we persuade a probably reluctant plumber to correct his own work?

I had a new unvented cylinder installed with new expansion vessels a year. See image of the red vessel (12 liter 130 Cal-Pro Zilmet) supported only with the two copper pipes. Another plumber recently warned us that this expansion vessel could become very heavy if it failed, as it fills with water. That could result in the pipes breaking and to hot water flooding the room. It could also cause injury. Do I need to secure the expansion vessel with a bracket against the wall?

Thanks very much for your comments. This came up, as I have to change a washer in a tap. I don't think the plastic piping is polyplumb, as there are no markings on the pipes. So there is already a mix of different brands, the T junction being polyplumb. The whole thing has been in place and fine for 20 years. The polyplumb T junction was probably added by a plumber who was extending the water for an extension. So I'll just leave it alone and switch off the water from the main to change the washer, like Iceverge suggested.

I think I can answer my own question. The cap of the T junction has the distinctive polyplumb brand markings. So I'll get a polyplumb isolator.

I have a sink and want to add an isolating valve for the taps. See photos. The 15mm plastic pipes are at least 20 years old or probably 30- 40 years old. Should I get a (a) plastic isolating valve and not worry about what brand it is. In other words, different brands are compatible with each other. (b) plastic isolating value of a particular brand (if so, please tell me what brand) (c) copper isolating valve, and if so do I get a pushfit or compression or either. (d) do not touch it. (the plastic pipes go under the floor). Grateful for any advice.