Ready to hire?

Post your job in minutes, browse real reviews and choose who to speak to.Post a job

Need some tips or advice?

Plumbing

Shower pump doesn't start - do I need a negative head shower pump?

Kit Lian 06/02/2026 - 7.59 AM

I live in a house with a cold water tank in the loft that feeds the heating system. My shower pump (salamander ct50 xtra) doesn't start easily, always needing a good shake of the shower head to get it going. Last night I replaced the shower head for a new one, and now it won't start despite shaking. The hot and cold pipes run from the shower pump to the shower via the loft - I think that extra resistance is making it much harder for water to flow therefore preventing the shower pump from starting. Would replacing it with a negative head shower pump fix the issue?

Are you a tradesperson and able to answer this question?

2 Answers

Anonymous user

Yeah, switching to a negative head (universal) pump like a Salamander CT Force TU series should fix it. Your CT50 Xtra is positive head only—it needs at least 2L/min gravity flow to trigger. The new showerhead’s extra restriction (plus loft pipe runs) drops that flow below the threshold, so no start even with shaking. Negative head ones activate on tiny pressure drops, no minimum flow required—perfect for borderline/low-gravity setups like yours. Quick test: Hold the showerhead way down low (floor level), full open—if it fires up, low head confirmed. Otherwise, yeah, negative head pump’s the reliable fix. Clean filters first though, cheap/easy check.

Answered2 February 2026

Anonymous user

It could be as simple as changing the shower head as it could be scaled up causing restricted flow so the pump switch doesn’t operate. High is also a factor if you have to lower it to get it to operate. But if the installation is done correctly and be in situation for a few years now, then it should have a non return valve fitted to each pipe near the outlet side of the pump and sometimes theses and seize or become stiff which also prevents flow for operation

Answered6 February 2026