gradual slow hot flow all taps

[TB204]

This is probably a basic one, but just wanted to check. Hot water flow to all taps has gradually been getting slower over time and the thermostatic shower now needs to be turned up hotter to get a reasonable shower temperature. Its a vented cylinder heated by an oil boiler and the cylinder stat is set to about 62 degrees. The cold feed all seems to be ok.
We're in a hard water area and from what I've read I suspect that the hot water feed from the top of the cylinder might have a build up of limescale that is limiting flow. Does this seem the most likely cause? and given that may be, can I check this without draining the cylinder? (i.e by shutting off the cold feed and then draining the hot taps?)
Appreciate any help,
Terry

 

[John.g]

Is the vented cylinder fed from a cold water storage tank, should be if its a vented HW cylinder. If the cold water is also from the CWST and is OK then worth checling for limescale build up as you suggest, and yes, just shut the cold water supplyw to the cylinder and open the lowest HW tap. Don't follow why the thermostatic shower setting needs to be increased except that the HW temperature isn't 62C, maybe check this with a household thermometer.

 

[TB204]

Is the vented cylinder fed from a cold water storage tank, should be if its a vented HW cylinder. If the cold water is also from the CWST and is OK then worth checling for limescale build up as you suggest, and yes, just shut the cold water supplyw to the cylinder and open the lowest HW tap. Don't follow why the thermostatic shower setting needs to be increased except that the HW temperature isn't 62C, maybe check this with a household thermometer.

Thanks for responding John. Yes, its a standard set up with cylinder fed from cold water tank in loft. With regards the shower, it is fed from the same hot water outlet from the top of the cylinder (tee'd into 15mm to the pump - not by me I hasten to add). So my thinking was the hot restriction and low flow compared to the cold meant I had to turn the hot higher on the shower valve to get a reasonable shower temp). Although the flow is low, the temp from the taps seems hot enough ... just slow.

 

[John.g]

Assuming the shower pump is a twin, with cold supply from the CWST & the hot from the HW cylinder and the mixed flow has gone slow plus the fact that the (Hot) flow from the taps is also slow then yes, remove the cylinder HW outlet pipe and have a look.

 

[TB204]

Assuming the shower pump is a twin, with cold supply from the CWST & the hot from the HW cylinder and the mixed flow has gone slow plus the fact that the (Hot) flow from the taps is also slow then yes, remove the cylinder HW outlet pipe and have a look.

Yes, that's correct John. Many thanks.
Unfortunately, its really tight for room and the way its been plumbed will make it tricky to get any movement on the pipes, but hopefully it'll be a little easier than it looks.
Thanks again.