Have you checked this?The cheaper service valves have a smaller flow diameter and may be restricting the flow more than previously. Similar if combined tails and service valves have been used. Also, ensure the tails are not kinked or twisted.
Yeah, no issues hereHave you checked this?
Did you use LSX?Yeah, no issues here
Not sure what that is - so no!Did you use LSX?
Like a silicon seal ️Not sure what that is - so no!
No, not anywhere near any pipework, valves etc.Like a silicon seal ️
No, all clear and fills to the top at normal rateAny crap in your tank?
Thank you for your detailed reply and suggestions.Its not unusual for the flow to the sink and toilet to be affected when running the bath if served by the same pipe. Are you sure this didn’t happen before and its become apparent after doing the works.
Usually, once the bath tap is running ok (¾”) any trapped air gets sucked out of the pipes if left running for a few minutes. Once the bath is running ok ensure the upstairs toilet is full and then try the downstairs taps allowing time for any air to be sucked out. If your new sink is downstairs with the modern small connectors it is possible there may not be enough capacity to suck out any trapped air.
If systematically going through each fitting (bath/sink/toilet etc) on the pipework doesn’t work you could try disconnecting a downstairs pipe and purging water into a bucket.
Last thoughts are whether you could have inadvertently” introduced” a blockage into the system (dropped / left something in the pipe or a bit of polystyrene floating on the tank entered the pipe when it was drained) and check the new gate valve / service valve on the cwst (both for size and operation.
Without knowing the specifics of the system its difficult to troubleshoot so its a case of methodically checking the system and keeping an open mind.
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local